around 500 to 700 lang yung switch. meron si erwin mahavishnu iirc.
di ganun kalaki yung difference from the middle position. just a bump in volume and slightly more mids. if you use a lot of gain, di gaano dinig yung difference. mas dinig on cleanish to slightly breaking up tones.
yung wiring, you can get off the duncan site. ang medyo tricky part lang is adding the grounding wire to the neck pickup if yours didnt come with a third wire for grounding the cover. most tele neck pickups come with the cover wired to the black wire kasi. you'll have to install a separate wire for it.