Speaker positioning requires a lot of patience IMO. It's taken me months to find the right speaker position/listener position for my S5s. Play around with toe in to get the 'best' balance of imaging and soundstaging (best being what you like most). Once you think you have it, then maybe consider adding some treatments to the wall behind the speakers. I use Vicoustics and it has really helped deepen and widen the soundstage.
Remember, have patience, and good luck!
Remember, have patience, and good luck!