QTR-Quadtone RIP

What's the difference between the files in the Profile directory vs 
files in the Quad directory? Also what's the difference between a gray 
curve and a linearization curve?  I'm starting to do some 
platinum/palladium printing, and have developed an appropriate 
adjustment curve (I have both an acv file as well as the input/output 
paramaters) but a: don't know whether to input those paired values in 
the gray curve or the linearization sections, and don't know whether 
to edit the file in the quad directory or the profile directory.  If I 
do edit the file in the profile directory, I don't think that's the 
file I select under the curve setup section of the printing interface.  
I'm using QTR for windows.  Thanks.