I've been flying a DP Edge for a couple of months now and I've got mine balanced at about 5 1/2" back.

From DPM's website:
"We have had a couple calls from 540T owners that felt the 6 inch CG is too far aft.
Therefore, we would like to recommend that EDGE 540T START at 5 inches and work your way back to what you prefer."

Sounds like you're pretty close where you've balanced now.