That was a good energetic start to my aural day @Russ.
 

I hate to say “stewm*c”, but they have nut seating files.
I bought one way back when (when £1=$2).

https://www.stewmac.com/luthier-tools-and-supplies/tools-by-job/tools-for-nuts-and-saddles/nut-seating-files.html
Use that carefully and the bottom of the nut slot should be flat, and perpendicular to the end of the fretboard.

Oh that would be good if you could, please. We can do some kind of deal.   @Boo I did a big tidy of my workshop over the last few days (for reasons that will hopefully become apparent next weekend,…   Read more»