Okay, we now have a German subtitle track for this project. Because the Blu Ray just didn't have enough language options! I tried to match the font/size/position/style of the existing subs, and they look great. I don't follow my own guidelines from Project Threepio, so they flash by a little fast for my tastes, but they use the exact same timing as the official subs, and that's what I want to go with in this case.

I also learned a bit about how to easily move single subtitles up to the top of the screen to avoid onscreen text, which I may be able to incorporate into my other project as an "all languages are now CIH-safe" update someday.

EDIT TO ADD:

I just verified BD-compatibility, so unless someone spots a problem on the clip, I'm going with this encode. The complete x264 encoding options I used were: --preset=veryslow --tune=grain --bluray-compat --fps=23.976 --force-cfr --vbv-maxrate=25000 --vbv-bufsize=30000 --crf=1 --level=4.1 --open-gop --slices=4