vh2q,

I would check that the wing, the tail surfaces and the fuse are all straight and perpendicular to each other when the wing is installed.
Yes, the fuse nose needs to be staright, or a left hand yaw will be introduced by that deviation.
The bank always follow a yaw movement for wings with dihedral.

Second, I would check the lateral balance.

Check this article:

http://masportaviator.com/2006/09/05...up-part-three/