I too would say to put the M22s in the rear surround position, and the QS8s on the sides. You will, in theory and dependent upon your specific room, get a little more "umph" in the rear surround channels with monopole/direct radiating speakers like the M22s. Our ears hear things better when they in in front of us and off to the sides a little bit, but a lot can be lost behind our heads, thus the reason for wanting a bit more "pin-point" sound shooting straight at the listening area and not so diffused like the QS8s.
Absolutely not slamming anyone's setup with QS8s for rear speakers. I used QS8s for side and rear surrounds for years, then shifted to QS8 side surrounds and M3 rear surrounds and liked it a little more, but that is my experience. I think that you will get great enjoyment with the M22s on rear channel duty and the QS8s on the sides.
