QTR-Quadtone RIP

I'm new to QTR and I'm still trying it out (haven't paid yet) so I'm 
just guessing, as well.  I'm supposing that the media type pull-down 
list must do something, otherwise it wouldn't be there and everything 
would then be done using ink limits and linearised curves.  I've been 
trying to develop curves for Portrico Premium Gloss paper and (at the 
moment) black-only printing with MIS ink on an Epson 1280.