Post processing with custom filters in Assetto, it'll take the overbearing glare away on sunny days and help a little with distant views. I use either Wagnums or the natural graphics mod. If your bridging wmr to steamVR and using the open VR launch, make sure you ram the pixel density to 2.0 in the settings, it'll help some with a clearer image. Competizione does a better job of things with more natural colours and depth, I've took seconds off all my times as the world scale with the car and track in VR is night and day better over the Corsa engine.
Ultimately your correct about the sweet spot, I tried the first HP headset, it was night and day awful compared to the Vive, the worst thing about WMR.
Take a look at the Project Cars 2 demo if you don't have the game, it can be made to look stunning.
Somebody else can tell you about screen door, i'm not technically versed.
There's an extensive Assetto Corsa VR thread, look it up.