My experience has shown that on most bipes, the upper wing should have about 1.5 degrees less angle of attack than the lower wing. Different planes can require more than this. I find that fine tuning the incidence of bipe can turn a dog into a ***** cat. Thrust lines are also more critical on a bipe than on a monoplane, at least from my experience. I find I usually need about 3 degrees right thrust and about 5 degrees downthrust to get one to fly well. It pays to experiment a little as small changes can give vast improvement. Rod