Oculus Passes Rotation and Controller Rotation but HMD Screen is Black

[RMKD]

Could we add some more specific instructions in the readme?

I'm running Godot 3.0.6 stable mono with an Oculus CV1 on windows with ovr_first_person.tscn from the AssetLib instanced as a node and am launching with F5 (play).

SteamVR boots and shows green and identifies the Godot executable. Rotation and position for both the headset and controllers come through great once I figured out I need to attach a script (is there a reason the launch script is not included by default in the .tscn in the AssetLib?) but the headset screens are simple black.

# attached to main scene node
extends Node

func _ready():

    print(ARVRServer.get_interfaces())
	
    var interface = ARVRServer.find_interface("OpenVR")
    if interface and interface.initialize():
        get_viewport().arvr = true

It seems like I'm missing something to trigger rendering on the headset itself. I see the readme mentions a problem with hdr support but doesn't provide instructions how to perform the recommended and it's not clear whether these issues are related.