QTR-Quadtone RIP

Hi all, I am new to QTR, using it to make digital negatives.  I am running CS5 on a MAC, I have installed the Adobe workaround for color management, http://kb2.adobe.com/cps/834/cpsid_83497.html, and printing to a 3880.  Following Clay's wonderful PDF, I printed out the ink separation TIFF and made a pt/pd print.  The whites are not perfect paper white, but I am thinking that may get taken care of later in the process (ASSumption??). It occurred to me this morning that I don't recall ever seeing an option for whether to use the photo black ink or the matte ink - or even how that would be done.  I ran across something on Ron Reeder's site (have the book, but must have missed seeing this issue in my reading) that said to use matte ink.  Does the difference between these inks matter much?  I will print out an ink separation page using the matte ink and test, but wondering what others have experienced?  thank you....lyle