QTR-Quadtone RIP

I'm seriously considering trying the new K7 inkset; however, I have a
fair amount of paper for which there are no profiles available -- in
particular Premier Fine Art 500 Hot Press Natural and Moab Entrada.
I'm wondering how well the Bradford Rag Natural White K7 profile would
work with these papers. And, in general, how much can these profiles
be tweaked/adapted for other papers using the sliders in the QTR GUI. 

Chris Hargens