Ok room is 15'6"w x 21'L x 8'H

I am sitting 13ft from the front L/R ....6' from the rear Backs and 7.5' from the sides.
I watch movies is 95% of the time, normal tv broadcast for major movies and sports.
I have MK 750's for the front three ........ what are the absoluet best options for my rears and sides. These 750's have wicked disspertion detail and clarity should I go with 7 of these all around ? or maybe three across the front and two rear backs and two QS8's or all QS8's for the surrounds.

Pioneer sc-1525
M80 HG Cherry