I want to change pickups of my Silo special (sss) to Dimarzio Rails (neck & bridge) ,middle will keep oringial stock , question is should I change Vol pot to 500k or not? thanks for your help!
From my experience with Dimarzio Area pickups which I put in almost all my guiars they sound much better with the 500k pots, and rail-type pickups should require 500k pots even more.
When you do the soldering I'd suggest to add the treble-bleed mode which should help with the consistency of the sound on different volume levels (again, from my experience, single-sized humbuckers gain a bit more from this mod than usual single-coils or stacked pickups)