Woohoo! Beautiful. Glad I got to see the coding method in action that you mentioned a while back. Debugging the lists must be a hell of thing! Or maybe you’re a very careful typer. But the conciseness is remarkable.
Actually I prepare initially using MuseScore version 3 I separate the parts and do a little bit of bodging. Eg I have to use tests equal to actual bar length rather than just a bar rest, and my method can’t cope with chords tied together or single note tied of more than two notes. I export the parts as musicxml files then run a Processing script to convert them to sonic pi format. I can then reinsert ties if necessary. It gets quite quick after a bit of practice.