After some fiddling around with LR4, I think I have basically figured out what adjustments to the separate color channel tone curves do, but I can't figure out how to use them in a useful way. Can use of these curves make adjustments to colors in a more effective or efficient way than adjusting white balance or hue in the HSL panel, or provide better split tone adjustments to a black and white photo than using the split tone panel? Any tips or links to helpful articles would be much appreciated.