The wing can be heated and twisted to achieve 3-4 degrees of washout. In my experience, washout doesn't help much. Even with washout, I haven't been able to move the CG back on my GP GB to get rid of its nose heavy flying characteristics. Still with washout, I get a deadly sudden tip stall. I think the main problem with the GB is insufficient V, stab area and the fat fuse blanking out the h. stab in side slip. The resultant, combined yaw and pitch instability at high AoA seems to cause sharp tip stalls regardless of washout. Delmar Benjamin flies his full scale replica GB at 18%. Considering that most conventional aircraft fly at 25-33%, that is a nose heavy condition, but it would help mitigate the small v. stab and h. stab blanking situation. The GP GB has a bigger h. stab than scale and smaller wheel pants than scale (ie less vertical area in front of the CG to create yaw instability) so it does tolerate the recomended CG (23% if memory serves) with the recomended, limited elevator throw to prevent the wing achieving too high an AoA that cases a tip stall. That's my story and I'm stick'n to it.