fwiw I use SMGa's in a room 13' x 30' x 8' and the balance is terrific with beautiful bass, however, I have them placed at one end of the room (about 5 feet out) not along the side wall like you want to do.
also fwiw the SMGa is supposed to be a better balanced speaker than the MMG which is supposed to be a bit bright
also fwiw the SMGa is supposed to be a better balanced speaker than the MMG which is supposed to be a bit bright