Thanks for all the great info guys!  I will have to experiment when I can go fly again ( we just got dumped on with 12" of snow and now the temps are in the single digits here[].  This particular plane is not one that I use skis with.

The plane in question does not use rubber bands to hold on the wing, it has a slot in the fuse where a tab on the front of the wing goes, and two nylon bolts hold the rear of the wing to the bottom of the fuse.

I was particularly careful to make sure I built the tail assy. square and symmetrical to the wing, the only concern I had with this ARF build was that I had to grind little notches in the rear of the motor mount to get the rear of the engine to fit in the non-adjustable motor mount provided.  I can see that the firewall has some right thrust built in, but am concerned that maybe I mounted the engine cocked even more to the right, as the engine sides under the mounting tabs are not parallel, the rear of the crankcase is wider than the front.

I'll try to get with a more experienced pilot next time I can and ask their opinion on the yaw issue.