Since Poita posted his samples I’ve been playing with the grindhouse colours too! I didn’t know about your LUT NevararGreat, thanks for re-posting! Looking forward to seeing a few scenes when they render.
As for the saturation, Dreamaster, I think you’ve done a pretty good job. I really like the very watchable colours of the Puggo Strikes Back 16mm which is also highly saturated and quite similar to your frames.
Because of fading, the grindhouse is really missing true blue, its blues either come out very navy or very cyan/turquoise/cerulean whatever you want to call it, which is why Poita’s German and British scans look so natural. I guess they’ve just faded less.