Okay, awesome. I can move the projector back as far as it needs to go. That's not a problem.
I don't know if my wife will let me do such a dark color on the ceiling, as she says it makes the room feel too small. Perhaps just painting the tiles directly above the screen a dark color would be okay? If not, how much vertical room would I need for the ceiling color to no longer be an issue? SS seems pretty dark right now, but that could be because of the shadows on it.