QTR-Quadtone RIP

I am using an Epson 1280 with UT2 inks. I am following the user's
guide for creating curves and it says I need to find the relative
densities of all the black/gray inks in order from darkest to lightest. 

Which inks do you use for this? The cyan position has a bluish ink
that I suspect is considered a toner ink as does the light cyan. The
yellow position has yellow ink which I expect is also a toner. Do I
use Black, Magenta, Light Magenta in that order as my Black/Gray inks
and consider the others as toners?

I would very much appreciate any direction on this.

Thank you.

Scott