Unfortunately I can't move the side speaker locations or go through the ceiling. There is a massive steel girder in the ceiling that is insurmountable and the wells on either side have a door/window in the way. I need to leave the side/rear speakers where they are.

Thanks for the advice, potatohead. Do you think the QS8s for the surrund speakers or would the QS4s cut it?

Now this is how you learn Philosophy :