That's just perfect - very nicely done indeed - with many thanks. Also - Tobias Hume! (I'm attempting to typeset in modern notation one of the pieces from his "Poeticall Musick" of 1607, for two lyra viols tuned ffeff and one bass viol.)
However, from looking at your score, there seem to be quite a few tweaks needed in order to move notes and letters around to get everything in the right place. I wonder if this could be made internal to Lilypond, so that, for example, calling "FrenchTab" would give you everything you needed?
Alasdair