Tried out some other codecs. Didn't find any that gave satisfying results. I thought I'd found a codec, but it took a long time to render and then didn't inverse telecine properly - I got a weird "blurring" effect on every interlaced frame for some reason, like Cinema Tools couldn't read it right.

I'm doing some experiments with rendering out some of the very red scenes as having a much lower saturation, and higher brightness. It gives them a much different look, but might let me get away with some of the worst offending shots.