He said, "I don't honestly remember, but it is proportionally the same place as a Nemesis II. One of the issues with the Bosta is that the center ribs are 10 inches, vs 9 on the Nemesis II, which pushes the honkin' motor out 10%. I used to put a Tigre as close to the leading edge as I could, and recess a Fawx about 1/4 inch into the LE."
Nemesis CG goes at the front of the spar. Spars are probably the same fraction of chord, so my guess was probably close.