I have a telecaster which I am rewiring. I want to be able to select series or parallel connection when the pickup switch is in the middle. I have found schematics and they all specify isolating the pickup cover wire for proper grounding. I have choice between a seymour duncan 1/4 pounder with no cover, just two wires. (I also have a humbucker with 2 wires + shield - no problem there). Is there a previous post or article that will explain how the grounding is achieved on a pickup with only two wires like the 1/4 pounder?