Yup!
It IS chugging away...
I just hope I didn't forget something essential and I'll have to redo it
Obvious solution for calibredb slowness would be to use it to "pass over" commands to a running Calibre (GUI or server), but that would mean a lot of work and I'm unsure it would be worthwhile.
I know a lot of programming languages, but Python is not among them, unfortunately...
perhaps it's time to correct this oversight
Thanks, for the time being