Thanks, yes that makes sense from a fret number point of view. Unfortunately from a violinist/fiddler point of view, the semitone notation does no good.
For example, on a violin, in the simplest 1st position:
(2nd string) A string: A open, Bb/B 1st finger, C/C# 2nd finger, D 3rd finger, E 4th finger or open E string
(3rd string) D string: D open, Eb/E 1st finger, F/F# 2nd finger, G/G# 3rd finger, A 4th or open A
So in first position on violin, "frets 1/2" are 1st finger, "frets 3/4" are 2nd finger, "frets 5/6" are 3rd finger.
I don't think fiddle players would want to bother trying to make this translation in their head while playing.
It would be great for fiddle players and fiddle tunes, to have a tab for fingering.
I don't think the semitone notation will do any good for violin playing in tab.
Let me know if there is a way in Lilypond for tab fingering in this case. Otherwise I'm not sure it's worth having the tab for violin/fiddle,
Thanks