I tried the "leading edge" rule of thumb on my Kadet and it was very sensitive to nosing over on the ground or while landing, so I went a bit further forward. The ideal is to have ample weight behind the mains to fight the tendency to ground loop, but not make it so heavy in the tail that the tail won't fly (lift up) before the rest of the plane when you're taking off. Remember, the position of the main gear will affect your c/g, but that balance is separate from the fore/aft balance of the plane while it is on the mains during takeoff. I added another set of blind nuts under my fuse and experimented with the position (took 3 tries) until I got what I wanted. It helped ground handling, and the takeoffs and landings could be done 2-point or 3-point.