Well its a tough room to work with for sure. I am fortunate as I bought a house with a room that is only for HT. As far as placement goes I can only suggest what has worked well for me and you will have to translate that to your own space. Something that bothered me for a long time was the fact that my LCR just disappear but the surrounds were easily located and just didn't blend cohesively. In my case having them up higher than I would have thought necessary solved these issues. The receiver can adjust for these differences when you run your calibration. When I moved my QS4's to the bedroom I had no choice but to put the speakers up high, one had to be above the closet door and as it turns out that was a good place for them. This is whre the rubber meets the road, just get them up and see what works.
