I had a Rega Planar 3 back in the early 90’s. I tried a few clamps and weights which were available at the time. Didn’t really make a difference and I never felt comfortable with a clamp/weight on the very short record spindle. I believe there was a quarter inch to three eights inch length of the exposed spindle for the weight and it scared the crap out of me. I was using a Sumiko BP Special (the naked cartridge) and was never crazy about the sound of the combination. I moved on to a VPI HW19 MK III and used the Rega RB300 arm with the VPI.