Wanted to share my experience in case there is someone else looking for a way to lighten up this config. Those old knobs weigh almost 5 oz and if you're a fellow weight weenee that is a place to cut some weight. Plus, I have always played with the plastic knobs so I kind of prefer the feel. Fender makes a stacked plastic knob for their preamps on the Jazz. The CTS pots of the old 62 design have a 17/64" bottom and a 3/16" top. The Fender plastic knobs are 3/16" and 1/4" respectively. I wondered, him, what if I widen the bottom up...its only 1/64" off. I bought a 17/64 drill bit from Home Depot and was able to order both sets of knobs for under 20 shipped (got lucky!) I make due with limited tools so I imagine some of you have a better way of doing this as I only have a hand drill. Since the knob was plastic I used a little of the no slip place mat to wrap around the knob. Before doing that I loosened the tightening screw which also helped for grip. Securing it in the clamp I carefully drilled and bored out the hole. It fit great and feels great too. I put a tiny dab of silicone lube on the top of the bottom piece to keep them from sticking together. (A problem with the metal ones too.) If anyone is wondering that is a series/parallel switch.