The two gliders that had wingerons that I flew were "Rotors" and "Turbos". Turbos were small light weight slope gliders with very thin wings, and FAST. They would roll faster than you could count. The rotor was a larger glider and also fast but not quite as manuverable. The biggest concern is keeping the pivot point slightly ahead of the center of liftthis keeps the load light and maintains stability. The easist way is to place the pivot point right on the CG, which convieniently is right were you want the main spar.