Digital BW, The Print

I am trying to figure our QTR with linux and using 
the appropriate profiles.

I noticed this link on the profile download section of the 
web site:  http://harrington.com/QTR/1280-UT2.sit

Should I be using this under linux?  Or, as the .sit file
would suggest, is this MAC specific?

Also, once I get the appropriate curve setup, I noticed that,
in the linux KDE print driver, that you can pick one or two
curves, then vary the percentages of each curve.

If I have, say a neutral curve, should I pick this for curve
one, and nothing for curve two, then make the percentage 
ratio 100/0 ??

Roy has a lot of documentation, and I have followed the .pdf
instructions under the files section of this website, but I can't
seem to "get my head around" figuring out QTR!

Any and all followups appreciated!