Thanks Ace & welcome to APC. This thread is bit out of date now although the topic never is.

Item 10 looks new. Who is including that, AllATPs? I will have to think about how drag reduction at the wing would affect one side more than the other. One thing to remember is the low-speed (ie. vmc) regime is one where the drag curve goes up exponentially with decrease in speed. So there is a lot of induced drag to begin with, and any change due to ground effect will receive an amplified effect. Ground effect would greatly reduce drag and it would affect the wings unequally since the wings are loaded unequally. That would be my theory anyway.