I haven't been following too closely, but I'm surprised that you used the Master Lift and Master Gain controls last. Those are always the very first things I touch when I do color work. Adjust lift so the blacks are at or very close to 0 (but not below), then adjust gain so the whites are at or very close to 100 (but not over). Of course, if nothing's pure black or white in the particular shot, I don't go all the way to 0 or 100.

And I wouldn't do the desaturating-the-bottom-portion-of-the-luma-scale thing you were talking about. Instead, I'd use the far left color wheel (shadows) to get rid of the color cast in the dark areas. It'll yield better results.

You're using Color, yes? Are you using just the Primary In room, or are you using some Secondaries as well?