I used to have a coil-tap switch on a pull-out volume knob.

But once I went to a Vintage Vibe Guitars VVG humbucker-shaped P90 neck pickup, I didn't need that any more. Full time single-coil baby, with all the richness and detail (and less noise) of a P90. No it's not exactly like if I had routed my guitar and put a real P90 in it, and it just is what it is. I freaking love it.

With most VVG pickups you can change the magnets in like 3 minutes. It was really fun getting to listen to Alnico II, alnico III, alnico IV, and ceramic in the same pickup in the same guitar. Very interesting, not to be missed.

So I set it up so that when you pull that knob, it switches from bridge pickup to neck and bypasses the tone knob so it's effectively tone knob on zero.

You can see that the green wire provides a path for the tone-cap's bleeding off of treble to ground to go either through the tone pot, or just switched to ground on the switch. It's possible to add another cap and/or resistor on the ground side of the switch to help shape the perfect instant wooman tone.

The other side of the switch either intercepts the neck pup directly (orange), or takes the output of the pickup selector switch (brown). So if the pickup selector switch is in neck position then pulling the knob will just change the tone stack. Good for experimenting to compare two values.