I can't comment on the M22s for mains but that is a pretty big room.

My living room is 15' x 16', 20'+ cathedral ceiling and the 12x10x8 dining room is open to it for additional space that probably gets close to yours. I was more comfortable in going with the M60s to fill that much space but some M22 owners here can fill you in better than I.

The M60's do a superb job by the way. I am very happy with my choice, helped along by folks in this forum.

With great power comes Awesome irresponsibility.