RE: Direction problem?
I would be willing to bet three burned out glow plugs that your negative wing to float incidence is indeed the problem compounded a bit by the CG at a half inch to the rear of the step. Most seem to work well with the step either at at or a quarter inch aft of the CG. As most of the responders have indicated one to three degrees positive wing to float is about ideal and I usually shoot for around two degrees.
Putting the step ahead of the CG will not provide those pretty float plane lift offs we all love so much and in my opinion will only agravate your t/o directional stability. This works in exactly the same way that a land plane with taildragger main gear when the wheel footprint is too far forward and the result is directional instability. The area immediately in front of the step when on the step is in effect of the wheel footprint. Move it further forward and always the result is instability.
John