I think you'll have to pull the red saturation down by a greater amount than that, since the faded film from which the GOUT was derived was already starting to become red-shifted at the time it was scanned.

Also, judging the whole movie by one level of red throughout isn't necessarily reliable, because it is likely to be inconsistent as to which shots are more faded and red-shifted, and which ones are not.

Puggo Grande isn't a totally accurate source either for a variety of reasons (it pushes blue entirely too much throughout the movie, for one thing), but even taking this into account, certain aspects of the original colour timing seem to be retained. Having just watched some it, I would say that the scenes of Luke lost in the snow should have their blue levels saturated a little bit more—not much, but a little—and the red dialed back somewhat. A subtle shift in each of these should combine to make the purple tint go away, and the scene come closer to what its original appearance probably was.

It does seem to me that the only shots in which Hoth's snow should have any significant blue saturation are the ones where Luke is lost, since it is intended to be colder and darker during this time. The amount of it ought to be less than Puggo Grande (and way, way less than the SE), but a bit more so than it currently is. By no means should this be taken to mean that each shot should be totally consistent with each other, as I'm quite certain that the original prints were nearly as variable on this matter as on the Death Star interior in the first movie.