Hey - yeah, I think that last one is about right! I'm not sure if that last break between ある and じゃろう is normal/intended, but I guess that's to keep it in line with the rest of the box? And yeah, I can see that it's auto-breaking at the 「 chars like it should.
Either way, as long as it stays within the bounding box and follows a reasonably consistent pattern for breaks, that's good enough for me. Let me know what the changes are, and I'll see if I can fit it into my version of STM. Thanks!