After some more fiddling with the weight maps, I think I'm now reasonably happy with the new jaw rig, so I had a go at making an injection pose for it. I learned three things:

1) My usual programming editor, VS Code, is very good at editing Poser files, I would claim better than Poser File Editor. It has an outline mode that is enabled by default and recognizes Poser's block structure, which makes copying large blocks around quite easy. The same might be true for other modern code editors, but doing that research is left as an exercise to the reader.

2) Injecting weight maps via a pose file works like a charm, BUT...

3) In the case of Antonia's jaw, that requires a bit of preparation in the joint editor, because the jaw actor does not have the necessary joint channels to influence other actors, in this case the head and neck. As far as I know, these channels can't be injected, but of course I could be wrong and there could be a special trick. If you happen to know the magical incantations, let me know. But that's actually not that relevant for Antonia herself, because distributing a modified CR2 is no problem, even when one is not me.

At any rate, the Antonia 1.3 CR2 with the new expression rig is becoming ever more likely to be a thing of the near-ish future. I'll probably still include the injection pose file plus instructions, so fans of Antonia-WM can spruce their favorite bendy lady up, as well. If anyone is super-keen to try that out yesterday, let me know and I'll provide the necessary files for testing.

-- I'm not mad at you, just Westphalian.