friend brought me a US G&L bass that had had its neck replaced with a non-G&L neck. The luthier shaped the headstock G&L style, and there are no markings at the butt of the neck. The hole in the headstock to access the truss rid nut is barely bigger than the hex wrench necessary. And the nut is way down there! The neck is at maximum tension and still too much relief. If I had to add washers inside, however would I do it? Drill the hole bigger? Why are necks made this way?