Mike, welcome. If you want to avoid having the mains in the walls, then neither the in-wall nor 1n/on wall units are suitable. You could use the regular M22s mounted on the walls, which would of course protrude a bit more.

Just looking at your diagram, the side surrounds(probably QS8s)should be directly to the side of the listening position in a 7.1 setup and the back surrounds just slightly wider than shown, about even with the outer edge of the couch.

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Enjoy the music, not the equipment.