Thanks, JohnK and Murph. I will experiment your suggestions. I believe my front L/R and my listening position do form an equilateral triangle with sides of 9-10 feet. Now how about the QS8s? Should they be placed wider/narrower/same distance apart as the front speakers? Or is it again something for the individual listerner to experiment?

Yamaha RXV3800; 2xM80, 2xQS8, VP150 and EP350v3; Panasonic 50" TV; PS3; Harmony One; Denon 3930CI