Chris, welcome. Yes, bookshelf speakers such as the M22s can and have been wall mounted, taking care to leave about 3" of "breathing room" for the back ports. In your size room the M60s would certainly do well and would have a bit greater maximum output capability. Especially since you'll be using a projection screen, I'd suggest that you consider having three identical speakers across the front, whether M22s or M60s, rather than a horizontally configured center.

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Enjoy the music, not the equipment.