So, I have a '96 Les Paul custom that is hard to tune. Seems to stay in tune and intonates well. But, it is difficult to tune. I go back and forth between whether I think it is the tuners or the nut. Some of the tuners seem to "skip gears". Questions: 1) Any recommendations on dressing the nut? 2) Are there any "drop-in" replacements for the factory Grovers? I don't really want to drill any holes. 3) Why does Gibson continue to use Grovers when so many people replace them?