I'm using a pair as (side) surrounds. I mounted them following Magnepan's instructions: the bottom of the panel is 20" off the floor and they are angled so that the tweeter is aimed directly at the sweet spot.
I'm about to experiment with something to dampen the backwave on the area of the wall directly behind them.
I'm about to experiment with something to dampen the backwave on the area of the wall directly behind them.