I think I would try them back there and you could just use the 'T' bracket they come with. If you like the way it sounds you are done, if you don't like it then I would suggest trying them slightly in front of the listening position above the pictures and slightly adjust the present speakers to the rear a little closer in to the middle away from the corner giving you a 7.1 system, then again the 7.1 system may just work very well with the rear speakers the way they are.


Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70