You'll find better advice from people other than me, but what would help is to get room dimensions as well as details about what gear will be running your speakers and what obstacles there may be in regards to speaker placement. Since it's to be a dedicated theater, I assume that won't be a real issue. As for the QS8s, many people seem to like them just fine as rear surrounds. I have to ask, however, why you're not mentioning side surrounds in your setup.