QTR-Quadtone RIP

I had posted this question on Digital B&W, The Print and got no response.  And now I've 
found this group.  So here it is again:

"The amount of solid information available on this forum [Dig. B&W, the print] is amazing. 
But,...but for some of us who are not professional or even very advanced amateurs, it can 
be a daunting task to extract what is needed to get a very good print from the means at 
hand. ( Even for those of us who are not techophobes.)

The question of linearization is clearly an important one, one that I'd like to
simplify for my setup. So, here's an inquiry that I'd like to get out of the way:

I've purchased QTR for use with my 2400. I've installed the profiles included for many of 
the popular paper choices. If I choose, say, SPR2400 Velvet Fine Art in the Printer Profile 
(Print with Preview), am I assured of a linear response? Or should I purchase the 
PrintFixPro spectrophotometer kit to do the job? And does this kit give me everything I 
need to profile any paper I choose? (I asked a related question, empasizing linearization, 
of the supplier, and he said he'd get back to me with an answer.)"  He hasn't.

TIA for your advice.

Harry