FWIW I have the H9 27% CAP232g with a DL50 in it and did nothing more than put the batts up in the engine box and used the pull-pull for the rudder like they suggest with a gasser. The CG is right where I want it with a roll to inverted on a 45 upline continues to climb for a bit then starts to level out. Just a slight bit of down needed to maintain level inverted. I had a lighter 45cc engine on it at first and the cg was at the rear suggested range. At that point it was almost hands off inverted, but still flyable. No added weight either way. I can't imagine adding 2 1/2 lbs to it.