I’ve taken some time to work through it, and I’ve figured it out
Not quite the original brief, but I think it might even be better. I’ve since strung her back up and she’s singing away. Hopefully someone somewhere will get something out of my needlessly specific project.
You wired it according to your diagram in post 21?
You've got your guitar strung up and its working in all positions as expected?
Because I don't see that it will work like you want in all switch positions from the diagram that you posted.
Yep all working correctly. Tapping the poles with a screwdriver shows the correct pickups are active, and strung up positions 2 and 4 have a very pronounced volume jump.
There are no volume dips, phase issues or incorrectly activated pickups across any positions.