CUT and GAIN, are adjustments you can do in the main menu, they have nothing to do with WinDAS. They're simply brightness and contrast for each color.
When you decide to go deeper and do the WinDAS adjustment, there is a guide by Spacediver here on Hardforum.
I tried finding hardware that would work with it to do a colour calibration, although old calibrators themselves are hard to find, and expensive. So WinDAS, unless it can do something on its own, unfortunately doesn't seem to be a solution for me.e