I want to install a stacked knob set of controls in a bass: vol/tone, EMG select P bass PU. It will be passive. As I understand it, 250k pots will yield a darker tone(please correct me if I'm wrong, but that's what I'm after). Are there stacked sets w/dual 250k pots? I've found 500k/500k & 500k/250k- would these be advisable? Links, suggestions or sarcastic comments are all welcome.