Mustang, I agree that 25% MAC is a good point to balance for a single wing (I like 30%, but 35% is too aft), but are you accounting for the lower wing? The CG should be a little further back for both wings combined (bottom wing is further aft). Mine was stable at the 4" mark per the manual, and I think this is about 25% MAC of the airplane (2 wings). Of course, a CG in front of the 25% MAC flys fine too, but when trying to balance this bird, it requires a lot of ballast.

I worked hard on some mods to move things forward and it paid off: electric version came to 8.7 lbs AUW.