Update: So I tried a different pot. It was an A250k as I didn't have any 500's. The tone tapered off nicely. Just the way I wanted it, with a much larger arc of change. So I will be pulling put all the pots and upgrading them to some decent quality 500's. I'll also be trying the old Kinman trick to try and stop the volume cutoff problem when in the middle position. Wish me luck. Updates to follow.