In the manual Tom suggests that the stab be zero'd then the lower wing zero'd to the stab and the upper wing at -1. He also states that you could leave the upper wing alone and build it as it is and there should be no problems. He does recommend the -1 for the top wing so that it stays flying a tad bit longer that the longer wing fopr slow landings.

Once I start mine I'm doing the -1 on the top.