Originally Posted by
Simon Barden
Ouch for the headstock!
You don't need to run ground wires to the cavities if you run tape over the top of the body so it makes contact with the taped underside of the pickguard, preferably running up to some of the screw holes so the contact area is under pressure. It's not quite so pretty with the pickguard off, but you can't see it when it's assembled and it makes taking it apart again a lot easier.
Also, have you checked the tape continuity with a multimeter? Even though there's an overlap between parallel lines of tape, I often find that I don't get any continuity all the way across the taped area unless I run some more tape at right-angles across the top of the other tape, when it's suddenly fine. I have no idea why this happens, but it does.