I found a relatively easy way to use QTGMC deinterlacing for some of my VHS captures
here. I'm using this method particularly because I know my way around ffmpeg much more than I know avisynth, and I'm adding a command in to change the DAR to 4:3 (the captures were in 3:2 for some reason).
However, I've learned one major issue. I've noticed that the final output doesn't appear to be in 59.94p. Sure mediainfo SAYS that it is in 59.94 frames per second, but just based on my visual observation, the interlaced version is simply smoother.
As a note, I used FFV1 as the lossless codec for the original captures, and I'm compressing them down to AV1. So if anyone has any ideas what might be causing this framerate issue, please let me know.
Thank you in advance.