https://mods.paradoxplaza.com/mods/75190/Windows
This mod allows you to easily change the capacity of school buildings based on their education level (elementary, high school, college, and university).
The mod uses these pre-set values by default (values relative to vanilla capacities):
- Elementary -> 200%
- High School -> 100% (unchanged)
- College -> 125%
- University -> 125%
You can also change these values yourself in the settings (restarting is NOT required).