In my 24x13x8 room, the VSM-MX's are 60" from front wall to tweeter face, 6'6" apart between driver centers. I'm sitting about 10-11' back, 5-6' behind me. I have Realtraps Mondotraps on all corners, Minitraps on both first reflection points, and an RFZ panel between them on the front wall. After much trial and error optimization and a few very productive discussions with Bobby they have stayed right there. YMMV, but a quick call to Bobby with your room dimensions will probably help you out more than anything.
Tom
Tom