@audiodidact:
I made the mistake of not looking at your Audiogon virtual system before suggesting the Vicoustic Multifusers. 3’ has long been considered the common wisdom for the minimum distance between planar loudspeakers and the wall behind them. Actually 5’ is much better, due to the speed of sound and the issue of the rear wave wall reflection arriving back at the planar panel and interacting with the panel’s front wave in a deleterious manner.
The rear wave should reach the listener’s ears at least 10ms (milliseconds) later than the front wave for those two sounds to be heard separately. Anything less, and the rear wave is instead perceived as a "smearing" of the front wave. Sound travels at approximately 1’ per ms, so a 5’ distance affords a 10ms delay between front and rear waves reaching the listener’s ears. 5ms from the rear wave to the wall, 5 more ms for the rear wave reflection to arrive back at the planar loudspeaker, thus a 10ms separation between the two at the listening position. Simple physics!
If at all possible, move your Maggies further away from the wall behind them. If you can, diffusion works great. If you can’t, perhaps absorption is the better choice.