QTR-Quadtone RIP

In a recent thread I had, Paul Roarke Suggested I use the BOOST_K= field, as I was having difficulty profiling UT14 to Epson Premium Glossy Photo Paper.  On the profile I have, Dmax is about 1.93.  I have got the Dmax up to 2.60, although this was when heavily saturating the paper, I would have thought I could possibly get up to about 2.20 without over -saturation.

I can't see any instructions on the literature I've found about this feature.  Could anyone point me to something or explain the use of this, in terms aimed at a TechnoKlutz.

I would also be interested in the use of the GRAY_HIGHLIGHT=, GRAY_SHADOW=,  The literature I have is a bit brief, stating that lowering from 10. lightens either the shadows or highlights.  Can you go above 10?  Is this a sort of try it and see feature?  Also the literature conflicts with one setting 10 as a default and the other 6, or some other.

I'm not sure of the GRAY_OVERLAP= feature either.

Ross