I am in the process of balancing my plane. Can someone explain exactly what I should do. I have the plane upside down, Its nose heavy I know. I place weight at the tail & cant seem to make it balance. The manual says 100 mm back from leading edge, done that.....then I'll try again with weight in a different spot on the tail & it will take more or less weight & want to balance somewhere else, either more forward or back, I,m confused........thanks, Dave