Conventional wisdom says move OB speakers as far out into the room as you can. I ran an experiment where I removed my OB monitors from the top of the dual servo sub cabinets and placed them on stands two feet further into the room. The room is 20' long, so now they're 7' from the front wall, and I sit about 5' from the back wall. Not surprisingly, this move made a noticeable improvement in sound, i.e., better soundstage, imaging and detail. The artists seem to be performing right there in my room.
I thought I was limited with placement, but hadn't considered using speaker stands in front of the woofers. Each stand consists of a single metal column, so they don't really block the subs' drivers, and they're WAF-friendly. The benefit of using speaker stands is the freedom to play around with placement, and to easily move the speakers out of the way when guests/children come to visit.