Do you have a second row of seating? Is it elevated? By how much?
Where is your center channel speaker going to go?
What are you doing for masking?
My ceiling is about 5" higher than yours. On paper, it appears I have enough room, but just barely. My second row of seating can just see the bottom of the screen. I'm going to need a MicroPerf screen to make room for the center channel, and I don't have enough room for motorized horizontal masking, so I'll be using some other solution.
I'd suggest drawing it out.