Well before you go chasing the thrustline issue, let's start with the simple stuff.

Does the yaw happen the same way every time i.e. always to the right? If not it is just normal crab due to cross winds.

Is the wing held on with rubber bands? If so is there a way to make sure the wing is in the same spot every time you put it on?

Is the rudder in line with the rest of the plane. Can you trim the yaw out with the rudder so that it doesn't happen at all? There is a chance that the plane is not "square' and will need a little rudder trim.

Tom
AMA 8026, instructor since 1995