I agree that it is too much for a hat channel. I haven't messed much with sound proofing a ceiling. I would more likely look at a sturdy mount on a rear wall, if that works, or mount to framing above the ceiling, and put the projector into that framing. Put a mounting plate on the fixed location, extend a pole through it, then soundproof between the pipe and dropped drywall.
I might look at AVS Forums on this one as there will be a fair bit more overall experience for this type of setup.