I can tell you that another plane is better for what you want to do, but what I did with my PT40 when I flew through a tree
after about its 30th flight was to order a new wing kit and I built it w/o any dihedral or washout,
it flew really good and quite a bit faster. It couldnt do knife edges but inverted flight was fun and really pretty stable and alot more aerobatic than the orig wing
Steve