Quote:

I am interested in the M-22s, but concerned about how far I have to keep from the wall due to the rear port.


Maybe 1-2 inches.
The closer to a wall, the greater bass response that occurs, but in general, the port distance doesn't do much unless the port is covered due to proximity.
My M60s stand about 8 inches from the back wall. In our old place, they were about 6 inches out (20.32 cm and 15.24 cm for those on the modern and more convenient metric scale).

"Those who preach the myths of audio are ignorant of truth."