I think about all you can do is try it out in a few different positions and see which orientation you like better.

Possibly trade in the M22 for a QS4 or QS8? that would be the better speaker for the rear center mounted flush right above the couch.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70