OK good effort and here is what I would do differently.
There are some things that pros look for in a great nut and here's what they are.
1) Does the shape and form compliment the instrument. More specifically is the nut minimalistic but appropriate for the instrument keeping in mind if the instrument is contemporary, vintage, what ever. We want the look to seamlessly let the eye address the instrument as a whole and not be drawn to the nut.
2) Are the nut sides flush with the neck sides AND remain flush following the shape of the fret board, headstock etc. This is why some makers finish the instrument with the nut installed first for that seamless look AND feel to the hand.
3) Is there excess material that could be removed. In our classes we teach our students to sacrifice a set of string in the nut making process. More specifically with a BAF (big arse file) we would once the nut slots are cut near final depth file all nut top material down until the file is hitting the strings. A bit scary until you do it and realize that it's very controlled and safe. This removes the excess top material and shapes the nut top to the break angle of the strings. Again this is done after the nut slots are cut to near final depth.
4) String spacing and yes yours are too close to the edge of the fret board. Any degree of fret end bevel and the strings are going to be coming off the neck. If you have Martin or Taylor guitar there go to school on the two outer E spacings in terms of how Martin or Taylor do it. Of course special considerations can change string spacing but most folks would be very OK with the spacing on either brand's nuts.
5) Nut slots and I know you had some trouble with this before so feel free to call me to discuss too during business hours, 734 332-6142. Slots would be approx. half the headstock set back angle from the fret plane. If the slot is too flat that's where that Ravi Cankersore sitar sound comes from. Slots should not have a hump in the middle either as mentioned above.
6) A really good nut will have an eloquent, complementary look to the instrument. It will be completely scratchless and so highly polished that a Master Jeweler may believe until he checks it out further that it's plastic. True story by the way. Micro mesh can give this highly polished look or use what we use a dedicated nut buffer..... no jokes please...
7) The nut slots themselves should have enough surface contact with the string that the strings are not riding on such a small area of bone that the nut wears prematurely. If you look at present day G*bson nuts this is what I am talking about. The contact point on the nut is so very minimal that the nut wears in no time.
Nut making can be an art and it can take any of us many, many nuts before we even start to see what others with more experience look for in a great nut so don't feel bad Mike.
I was in the same boat when I asked a local Luthier to put together a set-up class for me. That was 10 years ago now..... and hundreds of nuts later.
The best advice that I can give you is to find a good example such as a Taylor or Martin nut and go to school on it.
![[headinwall]](./images/smilies/headbangwalluf8.gif "Mad")
