Busted, I just finished mine and have not yet flown it. I balanced it at 13.75cm from the root leading edge with a Saito 125 and a 2200mah battery up front. I based my CG guess on splitting the difference between the manufacturer's suggestion of 12.5cm to 15cm from leading edge. Since you have had successful flights, can you tell me where your's is balanced? Also, what control surface throws did you use for initial flights?

Thanks for the help.