That's a legit cave at the moment. Sweet plans. I'm also thinking of going with a projector setup. Never thought of going anamorphic screen. I can fit about a 110" 16x9 screen. Are most blue rays 2.35? I am definitely out of the loop as most of what I watch is via a fire stick.
If your watching mostly movies then I would go with a 2.35:1 screen. Very few movies now days are 1.85:1, even nextflix originals are 2.01:1. I really like not having black bars, and being able to hide the speakers behind the screen. Here is my old setup.