I havent read the whole thread but some people were saying that the treble mod capacitor doesnt do anything when the volume is fully open.
Looking at the way it is wired, I have to disagree. The cap is like a bypass to the volume pots resistance so that the highs go straight to the output.
Some of you might not know but a volume pot is there to control the amount of sound from the pickups that DOESN'T get thrown away, thats why bigger resistance values for the pots gives you more sound (highs) as it is letting less sound get thrown away to the ground of the wiring. When you have your volume pot fully open, the resistence value isnt 0ohm, its 500k (if the pot's value is 500k).
I have a single coil and a humbucker on my guitar and no pots at all. Its like pickups -> switch -> output.