A pot has a resistance value that determines how much of the signal is bled to ground. The most common values for guitar pots are 250K and 500K. The higher the value, the more treble you will hear. In guitars, there are two taper types that are used in guitars more than any other. 1) Logarithmic, commonly known as an audio taper, and 2) Linear: with it's taper, treble cuts off quickly early in the turn of the knob. With an audio taper, the treble decreases much later in the turn. A 250K pot is generally the most useful resistance value for a bass guitar. Many bass pickups sound best when connected to a 250K volume pot. At full volume, there is plenty of treble response that’s suitable for all playing styles. New strings sound great, old strings sound great, fret clack is there for slap style, and so on. What would happen if you installed a 500K or greater volume pot? You’ll get more treble response, but probably not the kind you would appreciate. It will be an “ice pick” like sound that’s harsh to the ears, even for something as simple as string drag noise when you move your fret hand from fret to fret. An audio taper volume pot is the most useful for a bass player. For bass players, the audio taper volume pot is preferred because you get use out of almost the whole turn of the knob.
Whether you are building, restoring or modifying a bass guitar, I've encountered several Bass-Pickup Manufacturers that also offer Pre-wired accessories, Controls and Systems. Here are a few well known options.
EMG offers several wiring options. The PA2, BTC, BQC & BQS EQ Controls and Systems to name a few. ==> EMG Accessories: https://www.emgpickups.com
Seymour Duncan offers several selectable wiring diagrams ==> Seymour Duncan Accessories: https://www.seymourduncan.com
Bartolini offers several wiring diagrams: ==> Bartolini Accessories: https://www.bartolini.net