Has anyone solved this issue?
I have the same problem - I want to install an OBP3 in a bass that has holes for 3 pots. The SK/PP version has stacked treble/bass and push-pull for the mid select, so only 2 pots for the tone control but then still need a blend and a volume.
I would like to keep the bass in a condition that I can return it to stock if desired, so a stacked volume/blend would be ideal.
Currently the output jack is on the front of the bass so my current ‘plan b’ is to put the 4th pot in the hole that currently holds the jack, because that will give me a nice layout, then install a new jack in the end of the bass. But I really would like to avoid modifying the wood if possible.