Ed, welcome to Axiom. Since in a 5.1 set-up there are no back surround speakers, it's better to set the side surrounds slightly(a foot or two)farther back than directly to the side. This lends a little "phantom" back surround effect. Your back of the room is shaped a bit unusually, but placing the QS8s farther back on the corner walls should be a bit better. Neither way would seem to be more "directly" firing than the other.
You might try some temporary placement in each position to compare the difference, if any.
