I do tend to disassemble and clean my engines and polish crankshafts and such as a normal proceedure. Also, the break-in of the Wasp is NOT what you would expect in a small engine. I find that following the written directions is a very good thing.
If there is a difference in performance between the Norvel and the Wasp it is due to two things I have noticed. Most of the parts are completely interchangeable, BUT, the Norvel has a bigger venturi and more advanced crank port timing. I am sure that these things contribute to the less reliable stunt run for the Norvel. The Wasp will deliver good power reliably with a suction draw tank. I will not trust a Norvel without pressure to the tank.
For stunt, give me bullet-proof reliable power over high power every time. I will design a model to suit the power I have, and be a much happier camper. I own just about every type of Cox, VA, Stehls, Norvel, and Cyclon modern engines, and just about every old 1/2 A you care to name, and I fly WASP/Jan venturi!