After acquiring some digital calipers, it looks like the fret scale is correct. I took the G string nut slot down to .005" above the frets, got the neck a little straighter, and it intonates better at 4th fret with the open B string and also 9th fret with the open E. Those were the major intonation issues, although in that first octave it was generally not good; now it sounds like typical guitar temperament. The other slots are probably a bit high in general too but the unwound G suffered the most from going sharp under tension etc. I might still try an Earvana but wouldn't mind keeping the bone nut In if it intonates OK with keyboards.