Well OK...I overview-ed your Link to your Thread in DTDC.
It seems painting a screen "IS" in consideration. It also seems that at first you were considering a 115" wide x 48' high screen. Why change?
I see two rows of seats as well. Plans to move the electronics elsewhere too (...thank goodness...)
The Soffit does work to limit your screen height, and obviously that was a factor in your having to raise your Riser height.
A word of advice....although with having painted the underside of the soffit Black it will help mitigate reflections, don't expect the Black used to be completely "anti-reflective" when the top edge of the Screen will be close. Flat Blacks usually tend to reflect a Blue-ish cast under such conditions, especially under bright content, and the entire underside of that Soffit will light up.
Surfacing the underside with this stuff :http://www.fpi-protostar.com/flock.htmhttp://www.fpi-protostar.com/hitack.htm
.....and you'll NEVER
have such issues.
I'd like to invite you to wander over to the DIY Screen Forum. Don't underplay your hand too much on the "painted screen" idea. And Brother, don't wait much longer to get that screen painted! Really, it should of been painted "Before" you applied the wall paint, and the latter cut in around a masked edge.
Spraying a screen is what is called for, as you will note that on Projector Central, that was the stated preference, but they tried to show that rolling was possible. Well while that is true, when creating a "perfect" surface, rolling just does not fit that job description. Spraying is very easy and affordable: http://www.gleempaint.com/noname.html
....and at this point, masking off the needed area is going to be easy, and very little re-rolling of wall areas will be required. We/I can provide you with timely advice and helpful suggestions on all of the aforementioned screen considerations, as well as any other aspect of your remaining build (...We are actually one of the best "One stop Shop" Forum on AVS
I personally like your Theater. I call 'em "Pocket Home Theaters", and done correctly, they can be veritable Virtual Reality Palaces.