@j_husker
Jim may have other ideas, but as this *is* a large room, you might want to consider adding a subwoofer now (I believe you have 7" drivers and a bass port on the rear). To get any bass, I think you may be trying to keep the speakers close to the 'back' wall for your ports to provide that for you. With more bass energizing/pressurizing the room you might be able to get your speakers to fill in the space 'above' a subs 'sonic base' providing you a 'foundation' as they should (you have a lot of volume), and could then pull them out closer to you.
I have found soundstage is a combiniation of vertical (front to back) and horizontal (side to side) placement. With Vandersteen's (as I have), Richard has a very good setup guide to follow in getting you close, then fine tune. Doing a bit of digging, your manufacturer recommends the width/spread should be 3/4 of your listening distance. Not for your particular speakers, but may be a guide to use.
Or, try something extreme. I had someone once recommend pulling the speakers out as close to the listening position as possible, then, incrementally, move them back until the soundstage begins to form. Once you acheive that, play with width/spread and fine tune the center image. It did work, but found I was essentially placing the speakers in my room as Richard recommends in his manual anyway. But, a neat experiment.
