OK here is the mandolin format. Just reach 7th fret and move to next string. I don't understand my have to get to the higher frets on the first string but it works for me.

It will either need:

%%tablature #1 pitch=G, 28 0 63 m_head m_note

added to the abc or

tablature #1 pitch=G, 28 0 63 m_head m_note

added to the format file.

A pitch=C instead of G, would work for std/jazz tuned tenor banjo or tenor mandola, etc.

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I'm not sure I'm going to be able to do the MD tab as the postscript in the format file only sees the first note in a chord but if you can point me to a couple of examples to look at although it seems unlikley at the moment, I might be able to think of something.

There is another way that tab can be produced via abcm2ps which may be able to do more but it's beyond anything I want to do and I think is for laying out tab manually rather than generating a simple tab. You would need to read through the file fmt.txt that comes with abcm3ps for this.