Well now,
You have brightness going both for and against you here. Plenty of Lumen Horsepower, but a large, white reflective surface (ceiling) and ambient light at times.
There is no doubt about your needing a painted solution that both improves perceived Black levels (2500:1
) and works to mitigate ambient/reflected light that is less intense than the Projected light but strong enough to adversely affect the image quality via wash out.
For a "better than average" screen, I need to know you screen size. Just looking at that Partition Wall, I'd estimate 45" x 72" = 85" diagonal. You could go a little larger width-wise except that Light switch prevents you from placing the Screen just low enough to avoid that Ceiling. Hence, you must restrain the actual Screen height to 45" .
Now that's not "all bad", but certainly it's not "all good" either because your Optoma must be placed correctly to perform well. It is a machine with no Zoom, almost no Lens offset, and a very short Throw.(4' 4" @ spec'd screen size) Well suited for a Table-Top position, except your necessary Screen position would require a pretty tall table. Ceiling mounted, it will be hangin' mighty low.
Must I presume this unit is already in hand and a "Done Deal"?
If so, under these circumstances I feel obliged to suggest a Basic Neutral Gray w/Poly of a 7.0 on the Munsell scale
Gallon Custom Tint
Behr UPW (1850)-Interior Enamel
496 Lamp Black
112 Brown Oxide
048 Medium Yellow
To 1/2 of the Gallon add 16 oz MinWax "Water Based" Clear Satin Polyurethane
You can fude on the darkness of the Screen just a bit with this alternative shade:
Gallon Custom Tint
Behr UPW (,1850)-Interior Enamel
372 Lamp Black
084 Brown Oxide
036 Medium Yellow
What sprayer do you have?
All things considering, the Screen selection is an easy do, and it's performance will be more than sufficient. Anything "Mo Bedder" will entail the use of Silver Fire at a 4.0 - 5.0 colorant level, but that also means going to a Michaels store, as well as ordering a few paints off line.
I'd hold off on that and focus on the mounting issues, as I see your needing to mount that critter higher than screen center, tilt it downward, then employ the Vertical Keystone feature to correct the Trapezoidal image.
Get an image up and "squared" within the confines of the available space. Allow for at least 2" of Trim, and crowd that Wall switch as close as possible so as to maximize the distance from the Top edge of the Screen to the ceiling.
No matter what, when your playing any Game or watching content that contains brightly lit scenes, when the lights are down, that ceiling will light up like it's a giant Florescent Fixture. The ultra dark Screen will help by both attenuating the intense light output of the Screen while deepening the Black levels and color saturation enough to work against washout caused by all that reflected light so close in the proximity of the Screen.
Ya know, even iffin' ya don't / won't paint the Ceiling directly above the Screen, since your such a picky F#%r, you should consider wrapping a 4' x 8' x 1/2" sheet of Foam Insulating Board with Black Velvet and Velco-ing it directly above the Screen. Or just spray that sort of lightweight sheet with Disney Color "Mouse Ears" and hang it. I would make a world of difference when the lights are down because having a room "Flash on-Flash Off" is horribly distracting.
Man, Im a'tellin' ya, don't talk about being picky, and wanting something better'n average, and then set the stage for disappointing results by not considering factors that work against your desired results. That makes no sense. Smart thinking can elicit solutions that give you most everything you want while avoiding the things you don't.
BTW, why did you cop that GT700? For the 3D feature?