Randy Brets is the "Bonne Man". He knows all thing bridge and nut. Buy from Randy or make your own. I get my bone from Petco. Yup, dog bones. Smell funky to cut and sand but you can make a bunch and be done with it. I often use dense hardwood for the bridge and nut. Both bone and dense wood work great. I don't know about the second ?
That's cool about the dog bones. Odd as a friend has an old gibson br9. No slotted nut but could do a behind the bar bend. The whole idea makes me curious. why if the string feeds and string spaces are right at the bridge area on that old br9 that it doesn't need slots or string guides at the nut.
We had a home built one the string space at the bridge were only very slightly off but the nut absolutely needed slotting? What the difference? I guess the behind the bar bends topic is secondary to why the strings are so outta place at the nut area..?
Guitars are usually tapered. The neck gets wider at it's heal. This makes the string spacing narrow at the nut and wide at the bridge. It's a matter of narrow for the fingering by the nut and wide for picking individual notes at the bottom of the fretboard. CBGs however often use straight fretboards that are narrow all the way down. Just 3 strings can do this easily. I think it is a matter of strength also. A tapered neck is stronger than a skinny straight neck. Trees are wide at the stump and narrow up in the branches.