From the NACA report I cited on another thread, as well as some of what Igor has posted, I believe that the sharpness of the stab leading edge depends on its chord and per-cent thickness, as well as on whether it is airfoiled. My impression is that flat, thin stabs need sharper leading edges than larger airfoiled ones, but I'm still asking this question myself. I felt that a turbulator thread glued along the leading edge of my small SkyRay .35 stab helped it. This is a more recent stabilizer, modeled after another of mine that seemed to work fine. The elevator t.e. has since been squared off and stab t.e. contour completed. It's still a WAG with room left to play.

SK

 How much stab can you effectively use on a nose heavy SkyRay? Ok well, it is three oz and change heavier from the first flip. Shy at least as much as the engine quits. It is short coupled and has no flaps....a wire glued to the LE of the wing might make it fly better.