diff --git a/generate-subsampling-config.py b/generate-subsampling-config.py
index bf499e9c0..900094959 100644
--- a/generate-subsampling-config.py
+++ b/generate-subsampling-config.py
@@ -14,7 +14,7 @@
 
 class Sample:
     group_by: Optional[List[str]]
-    size: Optional[int]
+    weight: Optional[int]
     min_date: Optional[str]
     max_date: Optional[str]
     excludes: Optional[List[str]]
@@ -38,8 +38,8 @@ def to_dict(self):
         if self.group_by:
             options['group_by'] = self.group_by
 
-        if self.size:
-            options['max_sequences'] = self.size
+        if self.weight:
+            options['weight'] = self.weight
 
         if self.min_date:
             options['min_date'] = self.min_date
@@ -57,9 +57,15 @@ def to_dict(self):
 
 
 class Config:
-    samples: List[Sample]
-    def __init__(self):
-        self.samples = []
+    size: int
+    samples: Optional[List[Sample]]
+
+    def __init__(self, size, samples=None):
+        if samples == None:
+            samples = []
+
+        self.size = size
+        self.samples = samples
 
     def add(self, new_sample: Sample):
         if any(new_sample.name == sample.name for sample in self.samples):
@@ -69,13 +75,14 @@ def add(self, new_sample: Sample):
 
     def to_dict(self):
         return {
+            'size': self.size,
             'samples': {
                 sample.name: sample.to_dict() for sample in self.samples
             }
         }
 
     def to_file(self, path):
-        print(f'Writing {path}.  n={sum(sample.size for sample in self.samples)}')
+        print(f'Writing {path}.')
         with open(path, 'w') as f:
             yaml.dump(self.to_dict(), f, sort_keys=False)
 
@@ -124,11 +131,9 @@ def write_region_time_builds():
         build_name = f"{region.lower().replace(' ', '-')}_{time.lower()}"
         filename = Path(SUBSAMPLING_CONFIG_DIR, f"{build_name}.yaml")
 
-        config = Config()
-
         # Global gets special treatment because it is not a region.
         if region == 'Global':
-            target_size = 5150
+            config = Config(size=5150)
 
             locations = [
                 'Africa',
@@ -177,10 +182,7 @@ def write_region_time_builds():
                             'year',
                             'month',
                         ],
-                        size=int(
-                            target_size
-                            * weights[location] / sum_location_weights
-                        ),
+                        weight=weights[location],
                         excludes=excludes[location],
                     ))
             else:
@@ -193,11 +195,7 @@ def write_region_time_builds():
                             'year',
                             'month',
                         ],
-                        size=int(
-                            target_size
-                            * WEIGHT_EARLY / (WEIGHT_EARLY + WEIGHT_RECENT)
-                            * weights[location] / sum_location_weights
-                        ),
+                        weight=(WEIGHT_EARLY * weights[location]),
                         max_date=time,
                         excludes=excludes[location],
                     ))
@@ -210,18 +208,14 @@ def write_region_time_builds():
                             GROUP_BY_GEOGRAPHICAL_RESOLUTION[location],
                             GROUP_BY_RECENT_TEMPORAL_RESOLUTION[time],
                         ],
-                        size=int(
-                            target_size
-                            * WEIGHT_RECENT / (WEIGHT_EARLY + WEIGHT_RECENT)
-                            * weights[location] / sum_location_weights
-                        ),
+                        weight=(WEIGHT_RECENT * weights[location]),
                         min_date=time,
                         excludes=excludes[location],
                     ))
 
         # Asia gets special treatment because two countries must be weighted differently.
         elif region == 'Asia':
-            target_size = 4375
+            config = Config(size=4375)
 
             locations = [
                 'Asia',
@@ -255,11 +249,7 @@ def write_region_time_builds():
                             'year',
                             'month',
                         ],
-                        size=int(
-                            target_size
-                            * WEIGHT_FOCAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                            * weights[location] / sum_location_weights
-                        ),
+                        weight=(WEIGHT_FOCAL * weights[location]),
                         excludes=excludes[location],
                     ))
                 
@@ -271,10 +261,7 @@ def write_region_time_builds():
                         'year',
                         'month',
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_CONTEXTUAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
+                    weight=WEIGHT_CONTEXTUAL * sum_location_weights,
                     excludes=['region=Asia'],
                 ))
 
@@ -289,12 +276,7 @@ def write_region_time_builds():
                             'year',
                             'month',
                         ],
-                        size=int(
-                            target_size
-                            * WEIGHT_EARLY / (WEIGHT_EARLY + WEIGHT_RECENT)
-                            * WEIGHT_FOCAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                            * weights[location] / sum_location_weights
-                        ),
+                        weight=(WEIGHT_EARLY * WEIGHT_FOCAL * weights[location]),
                         max_date=time,
                         excludes=excludes[location],
                     ))
@@ -307,11 +289,7 @@ def write_region_time_builds():
                         'year',
                         'month',
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_EARLY / (WEIGHT_EARLY + WEIGHT_RECENT)
-                        * WEIGHT_CONTEXTUAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
+                    weight=(WEIGHT_EARLY * WEIGHT_CONTEXTUAL * sum_location_weights),
                     max_date=time,
                     excludes=['region=Asia'],
                 ))
@@ -327,12 +305,7 @@ def write_region_time_builds():
                             'year',
                             'month',
                         ],
-                        size=int(
-                            target_size
-                            * WEIGHT_RECENT / (WEIGHT_EARLY + WEIGHT_RECENT)
-                            * WEIGHT_FOCAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                            * weights[location] / sum_location_weights
-                        ),
+                        weight=(WEIGHT_RECENT * WEIGHT_FOCAL * weights[location]),
                         min_date=time,
                         excludes=excludes[location],
                     ))
@@ -346,18 +319,14 @@ def write_region_time_builds():
                         'year',
                         'month',
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_RECENT / (WEIGHT_EARLY + WEIGHT_RECENT)
-                        * WEIGHT_CONTEXTUAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
+                    weight=(WEIGHT_RECENT * WEIGHT_CONTEXTUAL * sum_location_weights),
                     min_date=time,
                     excludes=['region=Asia'],
                 ))
 
         # Everything else is a "standard" region with dynamic geographical/temporal grouping.
         else:
-            target_size = 4000
+            config = Config(size=4000)
 
             if time == 'all-time':
                 # Focal sequences for region
@@ -368,11 +337,8 @@ def write_region_time_builds():
                         'year',
                         'month',
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_FOCAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
-                    excludes=[f'region!={region}']
+                    weight=WEIGHT_FOCAL,
+                    excludes=[f'region!={region}'],
                 ))
 
                 # Contextual sequences from the rest of the world
@@ -383,11 +349,8 @@ def write_region_time_builds():
                         'year',
                         'month',
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_CONTEXTUAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
-                    excludes=[f'region={region}']
+                    weight=WEIGHT_CONTEXTUAL,
+                    excludes=[f'region={region}'],
                 ))
             else:
                 # Early focal sequences for region
@@ -398,11 +361,7 @@ def write_region_time_builds():
                         'year',
                         'month',
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_EARLY / (WEIGHT_EARLY + WEIGHT_RECENT)
-                        * WEIGHT_FOCAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
+                    weight=(WEIGHT_EARLY * WEIGHT_FOCAL),
                     max_date=time,
                     excludes=[f'region!={region}'],
                 ))
@@ -415,11 +374,7 @@ def write_region_time_builds():
                         'year',
                         'month',
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_EARLY / (WEIGHT_EARLY + WEIGHT_RECENT)
-                        * WEIGHT_CONTEXTUAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
+                    weight=(WEIGHT_EARLY * WEIGHT_CONTEXTUAL),
                     max_date=time,
                     excludes=[f'region={region}'],
                 ))
@@ -431,11 +386,7 @@ def write_region_time_builds():
                         GROUP_BY_GEOGRAPHICAL_RESOLUTION[region],
                         GROUP_BY_RECENT_TEMPORAL_RESOLUTION[time],
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_RECENT / (WEIGHT_EARLY + WEIGHT_RECENT)
-                        * WEIGHT_FOCAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
+                    weight=(WEIGHT_RECENT * WEIGHT_FOCAL),
                     min_date=time,
                     excludes=[f'region!={region}'],
                 ))
@@ -447,35 +398,27 @@ def write_region_time_builds():
                         'country',
                         GROUP_BY_RECENT_TEMPORAL_RESOLUTION[time],
                     ],
-                    size=int(
-                        target_size
-                        * WEIGHT_RECENT / (WEIGHT_EARLY + WEIGHT_RECENT)
-                        * WEIGHT_CONTEXTUAL / (WEIGHT_FOCAL + WEIGHT_CONTEXTUAL)
-                    ),
+                    weight=(WEIGHT_RECENT * WEIGHT_CONTEXTUAL),
                     min_date=time,
                     excludes=[f'region={region}'],
                 ))
 
-        # Double check the total sample size.
-        total_size = sum(sample.size for sample in config.samples)
-        assert target_size == total_size
-
         config.to_file(filename)
 
 
 def write_reference_build():
-    config = Config()
+    config = Config(size=300)
     config.add(Sample(
         name='clades',
         group_by=['Nextstrain_clade'],
-        size=300,
+        weight=1,
     ))
     filename = Path(SUBSAMPLING_CONFIG_DIR, f"reference.yaml")
     config.to_file(filename)
 
 
 def write_ci_build():
-    config = Config()
+    config = Config(size=30)
     config.add(Sample(
         name='region',
         group_by=[
@@ -483,9 +426,9 @@ def write_ci_build():
             'year',
             'month',
         ],
-        size=20,
+        weight=2,
         disable_probabilistic_sampling=True,
-        excludes=['region!=Europe']
+        excludes=['region!=Europe'],
     ))
     config.add(Sample(
         name='global',
@@ -493,7 +436,7 @@ def write_ci_build():
             'year',
             'month',
         ],
-        size=10,
+        weight=1,
         disable_probabilistic_sampling=True,
         excludes=['region=Europe'],
         # TODO: add Priority(type=proximity, focus=region)
diff --git a/subsampling/africa_1m.yaml b/subsampling/africa_1m.yaml
index 82b77d405..a1bf12e9e 100644
--- a/subsampling/africa_1m.yaml
+++ b/subsampling/africa_1m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 1M
     exclude:
     - region!=Africa
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 1M
     exclude:
     - region=Africa
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 1M
     exclude:
     - region!=Africa
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 1M
     exclude:
     - region=Africa
diff --git a/subsampling/africa_2m.yaml b/subsampling/africa_2m.yaml
index 794ea941a..ae7b79fe2 100644
--- a/subsampling/africa_2m.yaml
+++ b/subsampling/africa_2m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 2M
     exclude:
     - region!=Africa
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 2M
     exclude:
     - region=Africa
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 2M
     exclude:
     - region!=Africa
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 2M
     exclude:
     - region=Africa
diff --git a/subsampling/africa_6m.yaml b/subsampling/africa_6m.yaml
index d0c9cf907..1c0375919 100644
--- a/subsampling/africa_6m.yaml
+++ b/subsampling/africa_6m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 6M
     exclude:
     - region!=Africa
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 6M
     exclude:
     - region=Africa
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 2560
+    weight: 16
     min_date: 6M
     exclude:
     - region!=Africa
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 640
+    weight: 4
     min_date: 6M
     exclude:
     - region=Africa
diff --git a/subsampling/africa_all-time.yaml b/subsampling/africa_all-time.yaml
index b8362000d..5aea3c3d5 100644
--- a/subsampling/africa_all-time.yaml
+++ b/subsampling/africa_all-time.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal:
     group_by:
     - country
     - year
     - month
-    max_sequences: 3200
+    weight: 4
     exclude:
     - region!=Africa
   context:
@@ -12,6 +13,6 @@ samples:
     - country
     - year
     - month
-    max_sequences: 800
+    weight: 1
     exclude:
     - region=Africa
diff --git a/subsampling/asia_1m.yaml b/subsampling/asia_1m.yaml
index 38f77ab2b..4c677cb7f 100644
--- a/subsampling/asia_1m.yaml
+++ b/subsampling/asia_1m.yaml
@@ -1,10 +1,11 @@
+size: 4375
 samples:
   asia_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 300
+    weight: 12
     max_date: 1M
     exclude:
     - region!=Asia
@@ -15,7 +16,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 200
+    weight: 8
     max_date: 1M
     exclude:
     - country!=China
@@ -24,7 +25,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 200
+    weight: 8
     max_date: 1M
     exclude:
     - country!=India
@@ -33,7 +34,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 175
+    weight: 7
     max_date: 1M
     exclude:
     - region=Asia
@@ -42,7 +43,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 1200
+    weight: 48
     min_date: 1M
     exclude:
     - region!=Asia
@@ -53,7 +54,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 800
+    weight: 32
     min_date: 1M
     exclude:
     - country!=China
@@ -62,7 +63,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 800
+    weight: 32
     min_date: 1M
     exclude:
     - country!=India
@@ -71,7 +72,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 700
+    weight: 28
     min_date: 1M
     exclude:
     - region=Asia
diff --git a/subsampling/asia_2m.yaml b/subsampling/asia_2m.yaml
index 25e1bbfb5..5ff8353fb 100644
--- a/subsampling/asia_2m.yaml
+++ b/subsampling/asia_2m.yaml
@@ -1,10 +1,11 @@
+size: 4375
 samples:
   asia_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 300
+    weight: 12
     max_date: 2M
     exclude:
     - region!=Asia
@@ -15,7 +16,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 200
+    weight: 8
     max_date: 2M
     exclude:
     - country!=China
@@ -24,7 +25,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 200
+    weight: 8
     max_date: 2M
     exclude:
     - country!=India
@@ -33,7 +34,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 175
+    weight: 7
     max_date: 2M
     exclude:
     - region=Asia
@@ -42,7 +43,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 1200
+    weight: 48
     min_date: 2M
     exclude:
     - region!=Asia
@@ -53,7 +54,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 800
+    weight: 32
     min_date: 2M
     exclude:
     - country!=China
@@ -62,7 +63,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 800
+    weight: 32
     min_date: 2M
     exclude:
     - country!=India
@@ -71,7 +72,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 700
+    weight: 28
     min_date: 2M
     exclude:
     - region=Asia
diff --git a/subsampling/asia_6m.yaml b/subsampling/asia_6m.yaml
index fe7c87116..1c618f114 100644
--- a/subsampling/asia_6m.yaml
+++ b/subsampling/asia_6m.yaml
@@ -1,10 +1,11 @@
+size: 4375
 samples:
   asia_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 300
+    weight: 12
     max_date: 6M
     exclude:
     - region!=Asia
@@ -15,7 +16,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 200
+    weight: 8
     max_date: 6M
     exclude:
     - country!=China
@@ -24,7 +25,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 200
+    weight: 8
     max_date: 6M
     exclude:
     - country!=India
@@ -33,7 +34,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 175
+    weight: 7
     max_date: 6M
     exclude:
     - region=Asia
@@ -42,7 +43,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 1200
+    weight: 48
     min_date: 6M
     exclude:
     - region!=Asia
@@ -53,7 +54,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 800
+    weight: 32
     min_date: 6M
     exclude:
     - country!=China
@@ -62,7 +63,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 800
+    weight: 32
     min_date: 6M
     exclude:
     - country!=India
@@ -71,7 +72,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 700
+    weight: 28
     min_date: 6M
     exclude:
     - region=Asia
diff --git a/subsampling/asia_all-time.yaml b/subsampling/asia_all-time.yaml
index 03902de86..1a9063129 100644
--- a/subsampling/asia_all-time.yaml
+++ b/subsampling/asia_all-time.yaml
@@ -1,10 +1,11 @@
+size: 4375
 samples:
   asia:
     group_by:
     - division
     - year
     - month
-    max_sequences: 1500
+    weight: 12
     exclude:
     - region!=Asia
     - country=China
@@ -14,7 +15,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 1000
+    weight: 8
     exclude:
     - country!=China
   india:
@@ -22,7 +23,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 1000
+    weight: 8
     exclude:
     - country!=India
   context:
@@ -30,6 +31,6 @@ samples:
     - country
     - year
     - month
-    max_sequences: 875
+    weight: 7
     exclude:
     - region=Asia
diff --git a/subsampling/europe_1m.yaml b/subsampling/europe_1m.yaml
index 7b6b13f22..f023fc520 100644
--- a/subsampling/europe_1m.yaml
+++ b/subsampling/europe_1m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 1M
     exclude:
     - region!=Europe
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 1M
     exclude:
     - region=Europe
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 1M
     exclude:
     - region!=Europe
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 1M
     exclude:
     - region=Europe
diff --git a/subsampling/europe_2m.yaml b/subsampling/europe_2m.yaml
index c6ae72450..e87979145 100644
--- a/subsampling/europe_2m.yaml
+++ b/subsampling/europe_2m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 2M
     exclude:
     - region!=Europe
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 2M
     exclude:
     - region=Europe
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 2M
     exclude:
     - region!=Europe
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 2M
     exclude:
     - region=Europe
diff --git a/subsampling/europe_6m.yaml b/subsampling/europe_6m.yaml
index 2cbe4910b..c96b24e01 100644
--- a/subsampling/europe_6m.yaml
+++ b/subsampling/europe_6m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 6M
     exclude:
     - region!=Europe
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 6M
     exclude:
     - region=Europe
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 2560
+    weight: 16
     min_date: 6M
     exclude:
     - region!=Europe
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 640
+    weight: 4
     min_date: 6M
     exclude:
     - region=Europe
diff --git a/subsampling/europe_all-time.yaml b/subsampling/europe_all-time.yaml
index 1a1c0556d..f8c1eb0b0 100644
--- a/subsampling/europe_all-time.yaml
+++ b/subsampling/europe_all-time.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal:
     group_by:
     - country
     - year
     - month
-    max_sequences: 3200
+    weight: 4
     exclude:
     - region!=Europe
   context:
@@ -12,6 +13,6 @@ samples:
     - country
     - year
     - month
-    max_sequences: 800
+    weight: 1
     exclude:
     - region=Europe
diff --git a/subsampling/global_1m.yaml b/subsampling/global_1m.yaml
index 0518c8a7f..c44f90b4f 100644
--- a/subsampling/global_1m.yaml
+++ b/subsampling/global_1m.yaml
@@ -1,10 +1,11 @@
+size: 5150
 samples:
   africa_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 150
+    weight: 30
     max_date: 1M
     exclude:
     - region!=Africa
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 200
+    weight: 40
     max_date: 1M
     exclude:
     - region!=Asia
@@ -24,7 +25,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 175
+    weight: 35
     max_date: 1M
     exclude:
     - country!=China
@@ -33,7 +34,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 125
+    weight: 25
     max_date: 1M
     exclude:
     - region!=Europe
@@ -42,7 +43,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 175
+    weight: 35
     max_date: 1M
     exclude:
     - country!=India
@@ -51,7 +52,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 100
+    weight: 20
     max_date: 1M
     exclude:
     - region!=North America
@@ -60,7 +61,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 90
+    weight: 18
     max_date: 1M
     exclude:
     - region!=South America
@@ -69,7 +70,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 15
+    weight: 3
     max_date: 1M
     exclude:
     - region!=Oceania
@@ -77,7 +78,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 600
+    weight: 120
     min_date: 1M
     exclude:
     - region!=Africa
@@ -85,7 +86,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 800
+    weight: 160
     min_date: 1M
     exclude:
     - region!=Asia
@@ -95,7 +96,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 700
+    weight: 140
     min_date: 1M
     exclude:
     - country!=China
@@ -103,7 +104,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 500
+    weight: 100
     min_date: 1M
     exclude:
     - region!=Europe
@@ -111,7 +112,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 700
+    weight: 140
     min_date: 1M
     exclude:
     - country!=India
@@ -119,7 +120,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 400
+    weight: 80
     min_date: 1M
     exclude:
     - region!=North America
@@ -127,7 +128,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 360
+    weight: 72
     min_date: 1M
     exclude:
     - region!=South America
@@ -135,7 +136,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 60
+    weight: 12
     min_date: 1M
     exclude:
     - region!=Oceania
diff --git a/subsampling/global_2m.yaml b/subsampling/global_2m.yaml
index 6691ec84b..54c247d98 100644
--- a/subsampling/global_2m.yaml
+++ b/subsampling/global_2m.yaml
@@ -1,10 +1,11 @@
+size: 5150
 samples:
   africa_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 150
+    weight: 30
     max_date: 2M
     exclude:
     - region!=Africa
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 200
+    weight: 40
     max_date: 2M
     exclude:
     - region!=Asia
@@ -24,7 +25,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 175
+    weight: 35
     max_date: 2M
     exclude:
     - country!=China
@@ -33,7 +34,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 125
+    weight: 25
     max_date: 2M
     exclude:
     - region!=Europe
@@ -42,7 +43,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 175
+    weight: 35
     max_date: 2M
     exclude:
     - country!=India
@@ -51,7 +52,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 100
+    weight: 20
     max_date: 2M
     exclude:
     - region!=North America
@@ -60,7 +61,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 90
+    weight: 18
     max_date: 2M
     exclude:
     - region!=South America
@@ -69,7 +70,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 15
+    weight: 3
     max_date: 2M
     exclude:
     - region!=Oceania
@@ -77,7 +78,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 600
+    weight: 120
     min_date: 2M
     exclude:
     - region!=Africa
@@ -85,7 +86,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 800
+    weight: 160
     min_date: 2M
     exclude:
     - region!=Asia
@@ -95,7 +96,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 700
+    weight: 140
     min_date: 2M
     exclude:
     - country!=China
@@ -103,7 +104,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 500
+    weight: 100
     min_date: 2M
     exclude:
     - region!=Europe
@@ -111,7 +112,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 700
+    weight: 140
     min_date: 2M
     exclude:
     - country!=India
@@ -119,7 +120,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 400
+    weight: 80
     min_date: 2M
     exclude:
     - region!=North America
@@ -127,7 +128,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 360
+    weight: 72
     min_date: 2M
     exclude:
     - region!=South America
@@ -135,7 +136,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 60
+    weight: 12
     min_date: 2M
     exclude:
     - region!=Oceania
diff --git a/subsampling/global_6m.yaml b/subsampling/global_6m.yaml
index ed16452aa..6d6a712d5 100644
--- a/subsampling/global_6m.yaml
+++ b/subsampling/global_6m.yaml
@@ -1,10 +1,11 @@
+size: 5150
 samples:
   africa_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 150
+    weight: 30
     max_date: 6M
     exclude:
     - region!=Africa
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 200
+    weight: 40
     max_date: 6M
     exclude:
     - region!=Asia
@@ -24,7 +25,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 175
+    weight: 35
     max_date: 6M
     exclude:
     - country!=China
@@ -33,7 +34,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 125
+    weight: 25
     max_date: 6M
     exclude:
     - region!=Europe
@@ -42,7 +43,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 175
+    weight: 35
     max_date: 6M
     exclude:
     - country!=India
@@ -51,7 +52,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 100
+    weight: 20
     max_date: 6M
     exclude:
     - region!=North America
@@ -60,7 +61,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 90
+    weight: 18
     max_date: 6M
     exclude:
     - region!=South America
@@ -69,7 +70,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 15
+    weight: 3
     max_date: 6M
     exclude:
     - region!=Oceania
@@ -77,7 +78,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 600
+    weight: 120
     min_date: 6M
     exclude:
     - region!=Africa
@@ -85,7 +86,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 800
+    weight: 160
     min_date: 6M
     exclude:
     - region!=Asia
@@ -95,7 +96,7 @@ samples:
     group_by:
     - division
     - month
-    max_sequences: 700
+    weight: 140
     min_date: 6M
     exclude:
     - country!=China
@@ -103,7 +104,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 500
+    weight: 100
     min_date: 6M
     exclude:
     - region!=Europe
@@ -111,7 +112,7 @@ samples:
     group_by:
     - division
     - month
-    max_sequences: 700
+    weight: 140
     min_date: 6M
     exclude:
     - country!=India
@@ -119,7 +120,7 @@ samples:
     group_by:
     - division
     - month
-    max_sequences: 400
+    weight: 80
     min_date: 6M
     exclude:
     - region!=North America
@@ -127,7 +128,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 360
+    weight: 72
     min_date: 6M
     exclude:
     - region!=South America
@@ -135,7 +136,7 @@ samples:
     group_by:
     - division
     - month
-    max_sequences: 60
+    weight: 12
     min_date: 6M
     exclude:
     - region!=Oceania
diff --git a/subsampling/global_all-time.yaml b/subsampling/global_all-time.yaml
index 6dd4cc5ae..02dcc124b 100644
--- a/subsampling/global_all-time.yaml
+++ b/subsampling/global_all-time.yaml
@@ -1,10 +1,11 @@
+size: 5150
 samples:
   africa:
     group_by:
     - country
     - year
     - month
-    max_sequences: 750
+    weight: 30
     exclude:
     - region!=Africa
   asia:
@@ -12,7 +13,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 1000
+    weight: 40
     exclude:
     - region!=Asia
     - country=China
@@ -22,7 +23,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 875
+    weight: 35
     exclude:
     - country!=China
   europe:
@@ -30,7 +31,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 625
+    weight: 25
     exclude:
     - region!=Europe
   india:
@@ -38,7 +39,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 875
+    weight: 35
     exclude:
     - country!=India
   north_america:
@@ -46,7 +47,7 @@ samples:
     - division
     - year
     - month
-    max_sequences: 500
+    weight: 20
     exclude:
     - region!=North America
   south_america:
@@ -54,7 +55,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 450
+    weight: 18
     exclude:
     - region!=South America
   oceania:
@@ -62,6 +63,6 @@ samples:
     - division
     - year
     - month
-    max_sequences: 75
+    weight: 3
     exclude:
     - region!=Oceania
diff --git a/subsampling/nextstrain_ci_sampling.yaml b/subsampling/nextstrain_ci_sampling.yaml
index 68796db1c..c4eff48d9 100644
--- a/subsampling/nextstrain_ci_sampling.yaml
+++ b/subsampling/nextstrain_ci_sampling.yaml
@@ -1,10 +1,11 @@
+size: 30
 samples:
   region:
     group_by:
     - division
     - year
     - month
-    max_sequences: 20
+    weight: 2
     disable_probabilistic_sampling: true
     exclude:
     - region!=Europe
@@ -12,7 +13,7 @@ samples:
     group_by:
     - year
     - month
-    max_sequences: 10
+    weight: 1
     disable_probabilistic_sampling: true
     exclude:
     - region=Europe
diff --git a/subsampling/north-america_1m.yaml b/subsampling/north-america_1m.yaml
index ef9467190..5d9d51633 100644
--- a/subsampling/north-america_1m.yaml
+++ b/subsampling/north-america_1m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 1M
     exclude:
     - region!=North America
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 1M
     exclude:
     - region=North America
@@ -21,7 +22,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 1M
     exclude:
     - region!=North America
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 1M
     exclude:
     - region=North America
diff --git a/subsampling/north-america_2m.yaml b/subsampling/north-america_2m.yaml
index 8e6687418..0b2254915 100644
--- a/subsampling/north-america_2m.yaml
+++ b/subsampling/north-america_2m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 2M
     exclude:
     - region!=North America
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 2M
     exclude:
     - region=North America
@@ -21,7 +22,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 2M
     exclude:
     - region!=North America
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 2M
     exclude:
     - region=North America
diff --git a/subsampling/north-america_6m.yaml b/subsampling/north-america_6m.yaml
index 12b01f18e..3bb4ed324 100644
--- a/subsampling/north-america_6m.yaml
+++ b/subsampling/north-america_6m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 6M
     exclude:
     - region!=North America
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 6M
     exclude:
     - region=North America
@@ -21,7 +22,7 @@ samples:
     group_by:
     - division
     - month
-    max_sequences: 2560
+    weight: 16
     min_date: 6M
     exclude:
     - region!=North America
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 640
+    weight: 4
     min_date: 6M
     exclude:
     - region=North America
diff --git a/subsampling/north-america_all-time.yaml b/subsampling/north-america_all-time.yaml
index 596bb4151..2dafb262a 100644
--- a/subsampling/north-america_all-time.yaml
+++ b/subsampling/north-america_all-time.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal:
     group_by:
     - division
     - year
     - month
-    max_sequences: 3200
+    weight: 4
     exclude:
     - region!=North America
   context:
@@ -12,6 +13,6 @@ samples:
     - country
     - year
     - month
-    max_sequences: 800
+    weight: 1
     exclude:
     - region=North America
diff --git a/subsampling/oceania_1m.yaml b/subsampling/oceania_1m.yaml
index 708a38329..de615689c 100644
--- a/subsampling/oceania_1m.yaml
+++ b/subsampling/oceania_1m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 1M
     exclude:
     - region!=Oceania
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 1M
     exclude:
     - region=Oceania
@@ -21,7 +22,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 1M
     exclude:
     - region!=Oceania
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 1M
     exclude:
     - region=Oceania
diff --git a/subsampling/oceania_2m.yaml b/subsampling/oceania_2m.yaml
index 556d30dd2..346eb713f 100644
--- a/subsampling/oceania_2m.yaml
+++ b/subsampling/oceania_2m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 2M
     exclude:
     - region!=Oceania
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 2M
     exclude:
     - region=Oceania
@@ -21,7 +22,7 @@ samples:
     group_by:
     - division
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 2M
     exclude:
     - region!=Oceania
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 2M
     exclude:
     - region=Oceania
diff --git a/subsampling/oceania_6m.yaml b/subsampling/oceania_6m.yaml
index b8ef10285..229b062c2 100644
--- a/subsampling/oceania_6m.yaml
+++ b/subsampling/oceania_6m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - division
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 6M
     exclude:
     - region!=Oceania
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 6M
     exclude:
     - region=Oceania
@@ -21,7 +22,7 @@ samples:
     group_by:
     - division
     - month
-    max_sequences: 2560
+    weight: 16
     min_date: 6M
     exclude:
     - region!=Oceania
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 640
+    weight: 4
     min_date: 6M
     exclude:
     - region=Oceania
diff --git a/subsampling/oceania_all-time.yaml b/subsampling/oceania_all-time.yaml
index 27287e899..094f9c448 100644
--- a/subsampling/oceania_all-time.yaml
+++ b/subsampling/oceania_all-time.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal:
     group_by:
     - division
     - year
     - month
-    max_sequences: 3200
+    weight: 4
     exclude:
     - region!=Oceania
   context:
@@ -12,6 +13,6 @@ samples:
     - country
     - year
     - month
-    max_sequences: 800
+    weight: 1
     exclude:
     - region=Oceania
diff --git a/subsampling/reference.yaml b/subsampling/reference.yaml
index 6b83fa03c..26272772e 100644
--- a/subsampling/reference.yaml
+++ b/subsampling/reference.yaml
@@ -1,5 +1,6 @@
+size: 300
 samples:
   clades:
     group_by:
     - Nextstrain_clade
-    max_sequences: 300
+    weight: 1
diff --git a/subsampling/south-america_1m.yaml b/subsampling/south-america_1m.yaml
index 341313c72..98c9bbb72 100644
--- a/subsampling/south-america_1m.yaml
+++ b/subsampling/south-america_1m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 1M
     exclude:
     - region!=South America
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 1M
     exclude:
     - region=South America
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 1M
     exclude:
     - region!=South America
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 1M
     exclude:
     - region=South America
diff --git a/subsampling/south-america_2m.yaml b/subsampling/south-america_2m.yaml
index fa90187ea..f9c1de7fa 100644
--- a/subsampling/south-america_2m.yaml
+++ b/subsampling/south-america_2m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 2M
     exclude:
     - region!=South America
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 2M
     exclude:
     - region=South America
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 2560
+    weight: 16
     min_date: 2M
     exclude:
     - region!=South America
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - week
-    max_sequences: 640
+    weight: 4
     min_date: 2M
     exclude:
     - region=South America
diff --git a/subsampling/south-america_6m.yaml b/subsampling/south-america_6m.yaml
index a6592bda1..8605bb273 100644
--- a/subsampling/south-america_6m.yaml
+++ b/subsampling/south-america_6m.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal_early:
     group_by:
     - country
     - year
     - month
-    max_sequences: 640
+    weight: 4
     max_date: 6M
     exclude:
     - region!=South America
@@ -13,7 +14,7 @@ samples:
     - country
     - year
     - month
-    max_sequences: 160
+    weight: 1
     max_date: 6M
     exclude:
     - region=South America
@@ -21,7 +22,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 2560
+    weight: 16
     min_date: 6M
     exclude:
     - region!=South America
@@ -29,7 +30,7 @@ samples:
     group_by:
     - country
     - month
-    max_sequences: 640
+    weight: 4
     min_date: 6M
     exclude:
     - region=South America
diff --git a/subsampling/south-america_all-time.yaml b/subsampling/south-america_all-time.yaml
index 5acb7afb1..ddad75bdb 100644
--- a/subsampling/south-america_all-time.yaml
+++ b/subsampling/south-america_all-time.yaml
@@ -1,10 +1,11 @@
+size: 4000
 samples:
   focal:
     group_by:
     - country
     - year
     - month
-    max_sequences: 3200
+    weight: 4
     exclude:
     - region!=South America
   context:
@@ -12,6 +13,6 @@ samples:
     - country
     - year
     - month
-    max_sequences: 800
+    weight: 1
     exclude:
     - region=South America