
It's not the greatest pic, but just above the prop is the "torque tab" (what I call it). Could it be possible that yours is out of adjustment/alignment? I know that it's there to compensate for the prop torque and I know it affects the steering, but maybe it could cause some of the listing?
I have a fin/tail on mine also, but I never had any listing issues before that install. I can't think of anything else that would have the effect you have after getting on plane.
ETA: Which way is the boat listing? With just you on board or is it the same regardless of the number of passengers & weight on board?