Sounds good. One thought -- looks like your room might have a bit of a peak at 94 Hz which you could reduce by having the fronts of the speakers about 3 feet from the back wall, ie speaker ~1.5 feet out from the wall. In that case you would probably want to put the speakers a bit closer together, say 7-8 feet apart ie 2-ish feet from the side walls. That separation should be fine if your listening position is 8-9 feet back.
Dumb question, do you see the listening position as 8-9 feet back from the wall, or 8-9 feet back from the fronts of the M80s (ie 11-12 feet back from the wall) ?
They're big speakers, you gotta think about these things
