I agree with you Peter on the forgiving nature of the Q's, but really they're meant to be mounted more vertically or at least on an angle from the ceiling or wall. An install like this would be awkward and likely comprise the surround to some degree, how much is anyone's guess.

Back to the OP. Is this an 8 ft ceiling? you couldn't use a ceiling bracket?

Half of communication is listening. You can't listen with your mouth.