My latest is the Giant Aeromaster. I have found that it flys best with the upper wing minus 1 degree relative to the lower wing. On all my quarter scale bipes (four of them), the upper wing has always given best performance with the negative (relative to the lower wing) incidence. Yes, it does sometimes take a little ingenuity to try the different setups but, so far, it has always been worth it due to the improved flight characteristics.