FWIW, and I think it’s mentioned in the README, none of the subtitles sync with Puggo out-of-the-box. All of the SRT files, even the 16mm one (which refers to the soundtrack variant, not Puggo’s particular release), are GOUT-synced and designed for 23.976 fps. I think I’ll just mark that SRT file simply “mono” in the future, now that it looks like there probably isn’t a different 8mm mono variant.
You have to pass them through a Perl utility to make them sync, and even then, the only ones that’ll work easily are the NTSC DVD ones due to the framerate difference. If you’re using SRT files, post-conversion, you’ll still have to change the framerate from 23.976 to 29.97, or inverse-telecine the video back from 29.97 to 23.976. Oh, and the subtitles assume you leave the trailer in place, but only subtitle the feature.
But I’m glad you got it working a different way. This info is mostly for anyone else who’s curious.