Wow! Works great, thanks Thomas. I like the second version using the lilypond #{#} ---- I can easily add markup for font, etc. Added a string-reverse to get correct order. I read "extending" several times, skimmed thru "internals", guile manual and R5RS and have been working on this in my spare time for a week --- thanks.
I realize that make-circle-markup is part of lilypond and not Guile, but is there a way I could have known about that and possibly other useful funcs? I realized from the error messages that I needed markup, but just couldn't figure out how to get it.
Also, is the "#:" in "#:circle" a naming convention or dereferencer or what? Is there somewhere to look that up? I don't have much of an understanding about this.
Should I have tried to make this a tinier example?
I wonder why normal fingering doesn't show up in the Tab Staff ...
Thank you, Robby (sorry for even more questions --- the more you know, the more you realize you don't know)