rcpilot-ajaxrc,

There are at least two things that can happen if the fin/rudder are too 'lopsided' with respect to the thrust line. One is that the swirling prop wash can give you some unwanted yaw at low speeds, probably most noticeable during takeoff. The other is that it could be hard to fly knife-edge, although it is not necessarily the symmetry wrt. to the thrust line that affects knife-edge.

banktoturn