I don’t know how G’MIC Curves [interactive] will behave. But if you want to compare G’MIC Curves also, then the following is handy:
You can lock movement of control points on the curves in one direction:
Shift-left mouse button, only movement in y direction possible
Ctrl-left mouse button , only movement in x direction possible
(In Windows, I don’t know if it is the same on Mac)
I asked David for this months ago. Ten minutes later on, this functionality was existing. But the descriptions of these interactions weren’t updated, so maybe some people here don’t know this functionality.