I planned to clean up the edges of the headstock with my router, using a plywood template. But when I actually got to this point, I realized it was a silly idea. First of all, the router is that large and heavy compared to the headstock, that I doubt if the result would be okay. And secondly, it is a handbuilt instrument after all, so I shouldn't attack it with powertools exclusively. That being said, I took a rasp, a file and some sanding paper and started shaping the headstock. I really enjoyed working this way and it came out better than I thought it would.

Then I went on with the truss rod. I finally found some blue masking tape and used it to cover up the open side of the U-channel. For glueing I used a slow setting epoxy (usable for 2 hours, setting time up to 6 hours), so I could position it well and clamp it without rushing.

At the moment, I'm busy building a jig to cut the fret slots accurately.