I have a Yamaha RX-V2300 6.1 Player. My set up is as follows:
M22ti's for Front
VP150 Center (Front)
QS8's Surround
M2i Center (Rear)
EP175 Subwoofer.

I am going to mount the M2i, on a swivel wall mount about 6' high and point it down towrds the listener. I want to Mount the QS8's on the wall as well. My question is where exactly and how high should these be? First do they set in line with the listeners place on the couch? Or slightly behind? With the construction of the QS8's I would assume in line with the listener. Second how high should they be. One manual I saw had them about 3 feet off the floor, this Yamaha Manual has them placed 6' high on the wall!!

No I know there are many types of surround speakers out there, so I am sure Placement varies based on the construction of the speakers. So what's ideal for the QS8?
I ask for a sepcific answer if possible, as It is a real pain to run wire behind an already existing wall! LOL! I would like to only have to do it once! Thanks everyone!