i have 4 QS8v2 speakers in my 7.1 system. 2 for surrounds and 2 for surround backs and they all work great. they are all placed based on a height of 3' from my seated listening position; all 4 speakers are that height. they are all mounted on the walls and work out incredibly well. the rears are 15' away from the sides and the effects are magical in 7.1 movies or matrixed 5.1 movies.
the two side surrounds use the T-brackets for mounting
the two rear surrounds use the power mounting brackets
here is a shot of 3 of the 4 speakers mounted in place. they look nice and they sound great on the wall. due to the construction of the walls and it's an old house i used surface molding and it came out really good. they generate an incredible sound field at the height they are mounted and really give the illusion of hugh open space. i don't think they need to be mounted much higher than 3' or so above your ear level in the listening position.
best of luck with whatever you do. please throw some pictures up when you do mount them as i'm sure folks would want to see it.
