My preference is to not use front wall or corner loading. I like Geddes technique for multiple subs. I'm a proponent of using the crawl to find the best acoustic places for my subs short of measuring everything.
Likewise, I wouldn't suggest putting your speakers any closer than 7' from each other, on center. (Mine are too close at 6' apart, but it's all I got.

)
End of the day, we all have to work with our rooms, and that means compromise. I redid my room solely as my listening room, so I had more freedom. The subs and front 3 are all asymmetrically placed to help avoid cancellations. The sub locations were chosen with the crawl, and each spot sounds very good. Together, they are an absolute delight.
How far from the side walls right now? even if you could milk 3" more on each side, that might make a world of difference!
