I generally use 250 K Audio Taper potentiometers for traditional single coils pickups such as Stratocaster, Telecaster, Jazz Bass, Precision Bass etc. For instruments with humbuckers, I like using 300 K or 500 K Audio Taper potentiometers. There are several other values that are used with active pickups and the majority of vintage instruments will use potentiometers between 250 k and 1 Meg. audio taper. A 500 k pot will allow more highs to pass than a 250 k audio taper potentiometer