Digital BW, The Print

I'm up and running with QuadToneRIP on Linux.  Now I'm trying to establish 
a set of curves that work well with my Lyson QuadBlack inkset.

The QuadToneRIP package includes a special CMYK document (inkpattern.psd) 
that I'm supposed to print out without any re-rendering or resampling, to 
see the individual effect of each ink.  Trouble is, I can't seem to print 
this document from GIMP (which is all I have in Linux).  The document 
displays in RGB Mode, and I can't find a setting equivalent to "Print Space 
= Same as Source".  When I print, the document looks like each ink tried to 
do its own thing in its own place (i.e., four "ghost" images).

I've created curves with CALIBRATION=YES in the ink descriptor file, and 
have loaded these curves in to the PPD driver.

So here are my questions:

--*-- Any ideas on what I'm doing wrong in GIMP with the inkpattern.psd file?

--*-- Is there an alternative way to come up with a set of curves in a 
Linux-only environment?

--*-- Any suggestions for reasonable starting values for the Lyson 
QuadBlack inks?

Thanks in advance,

Allan