Hiccup, I consider your well thought-out classical tutorial to be in two parts, the first on how to use Picard, and the second on how to integrate those scripts into MusicBee. Should I post the questions I posted here, in the 'classical tutorial' Tips & Tricks thread? It appears that my problem is NOT with the classical threads in particular, but in not understanding how custom tags (with scripts) work in Music Bee. Since the scripts are copied directly from Page 1 of the Tutorial, I assume there are no errors in them.
If I go to Edit Preferences, etc. as in my previous comment, I can create the custom tags. But if I right-click on the track and select Tag Inspector, I see only ARTIST, ENCODER, and TITLE, and if I select Tags(2), I see the renamed custom 1 tag, but none of the virtual tags created under Define New Tags.