Do you think it's a mistake orientating things the way I've proposed?
If I go down the path of projection, I was going to build a slotted piece of plywood for the ceiling so that I could recess the entire screen into the ceiling and drop it down on demand. The joists run in a friendly direction for this.
The wall you suggested would definitely be better for a full false wall. I just don't want to end up flipping the couch around every time I switch between TV and projection
Also, I may as well run some cables for 4 subs, even if they'd be late additions.