Digital BW, The Print

I want to make a "cool" curve set for Ilford Smooth Pearl using UT2 
inks. Comparing the neutral and cool curves for EEM, for example, 
shows a non-linear relationship between the two. In other words the 
R, G, and B curves have different shapes. Therefore it appears that a 
simple mathematical offsetting of curves will not work to give a 
linear stepwedge of a singe tone. Does anyone know how these UT2 
curves are generated? Is special equipment required? Or perhaps there 
is an art to these curves that requires a lot of experience.