It looks like you have made your decision, but just wanted to add that I had to add weight forward as well. The battery is under the tank, I have a weighted prop nut, and have added lead in the engine well. I have a OS91 surpass, and even the extra weight of it still did not help that much. BTW: Mine flies great, it is one of my favorites to fly. One thing it did though, I replaced the inner ny-rod with a steel one. I found that temp changes did affect my trim on both the rudder and elevator.