Look away now if you're squeamish, today I sanded the nut shelf on the project Mockingbird.
To do this I made another makeshift tool. Using a rotary trimmer I cut a piece of sandpaper the same width as the nut then stuck it to a piece of wood with double sided tape. I slackened the strings off and held them out of the way while I carefully sanded the nut shelf, trying to keep it as flat as I could.
This seemed to work OK, I put the guitar back together and there were no disasters, but I really haven't taken anywhere near enough off yet. If I fret a note at the first fret you can see I'm bending the string down hard towards the fretboard as much as I am fretting it. This ruins the intonation at low frets and makes the guitar tiring to play and I've come to the conclusion this is why I've never really liked it.
So I'm going to have to repeat this process, perhaps actually measuring how much I'm taking off this time. There is probably some special jig a real luthier would have for doing this kind of thing, I'll just continue with the bodgery.