If this is to be a "permanent" screen, you should buy some good quality rollers, 3/8", and prime the wall (unless it's already white) with Kilz. To be as nice as possible, also consider wet-sanding between the coats of...
If you want a 100" image, you only have a few options: paint the wall or get an oversized piece of board. Go with the wall first. If it works for you, you're done.
I have a few of the small DV52si indoor/outdoor model hanging on the ceiling in the back surround positions. Love them. In 7-channel stereo mode I'm amazed at the reproduction from these little guys. I recommend to any...
I have 602s and the 600 center with the Denon 3803. A good match in my opinion. But for the 604s, I'd probably go for more power. The 3805 would work, but the full potential of these speakers really needs an amp with more oomph.
You, of course, realize that a 120" diag 4:3 screen stands 6' tall? With a center speaker "close" to listening height of around 2.5-3.5', your room would need 9' ceilings. And you'd probably need a >$10k scaler to...
Keystoning shouldn't be much of a problem, if any. With an HP screen, you want the pj to be closer to the middle of the screen to get the full gain (as you mention). Ceiling mounting isn't a great option as you sacrifice much or all of...
The purpose of painting the walls and ceiling is to minimize the secondary reflections that can wash out the image. Notice in any local cinema that you won't find any white walls.
Sounds like a plan, although I think I'd just cut off the extral 11" of material before mounting. Give it a better finished look when masked off. Should be easy to cut with a utility knife and a straight edge.
I have no...
How about building (or buying) a stand on which to place the projector? Say at 54-60" from the floor (above your head when you sit). It sounds like you're sitting behind the pj now? You must be WAY back if so. If I were in your...