Hmm… I thought this was going to work, but it seems it doesn't.
So, what I went for, was to use the two push/pull pots already in the guitar as switches for P90/Series operation.
Doing a tap-test on the poles, in P90 mode, it didn't seem to isolate the rail. I still get noise. Also, plugging into a high-gain amp, I saw no increase in noise from P90 mode (switch pulled up) which I expected to hear.
Any ideas of what I F'd up?
BTW, here is how the P-Rail runs…