Regarding the pickups: is there any way to know if I did damage anything by moving the poles? I mean, if something goes wrong during this operation = pickup not working at all, or is it a more subtle thing?
Don't know about damage, but I did have a Jazz where the E and G pickups were lower than the A and D strings. Did not care for it at all. The A and D seemed to jump out at you while the E and G seem to be almost dead in comparison. My RW Jazz has all even pole pieces, not raised at all, and it's the most even tone up and down the neck of any Jazz I've ever owned.
