You have a good sized room for HT. Unlike yourself I don't have a decent room so have to compromise.
I object to having surrounds or back speakers parked too close to listening chair, even with time delays. So in my room I opted for long wall placement and use reflections by placing speakers in the corner or have them reflect off side or front walls. Seems to work quite well.
![Smoking :smoke:](https://www.audiocircle.com/Smileys/audiocircle/sm_smoke.gif)