I just realized I may have hit another snag. This thread doesn't have a lot of traffic, so I may have to pose this questions elsewhere. I can't believe with all my researching and planning that I missed this one. Someone above asked about my equipment plans, which made me think about my projector. I have an older Mitsubishi HC3800. The picture still looked great, I had noticed the picture didn't pop as much as it once had, but a new bulb is still cheaper than a new projector right now (which isn't in the budget with the rest of the theater to finish).
Anyway, here's the dilemma. I have 10' ceilings. But I added a soffit around the room which dropped the perimeter down 13". And then, I obviously added the two risers for a total of 16". The stage is around 8" tall (going from memory, I'm at work). I don't have a place for an equipment rack, so I will have to have cabinetry under the screen to house electronic items like my HTPC, inuke, etc. I had considered the throw of my projector for the approx screen size that I wanted; however, I hadn't paid attention to the fact that when ceiling mounting that the calculator on proj-cntrl suggests that the bottom of the lens be 26" above the top of the screen for 2.35 or 18" for 1.78. Ouch. I need to throw all this in CAD, but if I have to drop down 2 feet from the 9' soffit for the top of the screen....then the bottom would be really low. I think that might not be the best experience with my taller risers. I assume the recommended drop is to avoid digital keystoning? I have read where some people with that projector "cheated" by angling the projector up slightly, and then correcting with keystoning. I don't know if that is an option, but does anyone have any suggestions or input?