Ok, so I went with the CineGrey 5D 16:9 120" as a starter screen.
I wasn't able to get the 5D in a Cinemascope for another 6 months due to it being a custom size, they only come in 16:9 for now.
This should get me as close to BD or DNP ambient viewing as I can for a good, budget friendly price.
I guess I'll be saving CinemaScope and AT for a future upgrade... to be continued.
Should get it in a few weeks.
Maybe I should request them to deliver it to my doorstep via drone, or maybe not.
Any slight miscalculation or bug in the flight code and it might end up dropping it off through the roof!
Buying a bucket of grey primer this evening for the theater walls. Lets see how far I can get tomorrow...