QTR-Quadtone RIP

This may be a really basic question, but I can not find anything on the 
web or within this group to find my answer. 

I am using an Epson 1800 printer, Windows XP, Epson ink and Photoshop 
CS3.  My results with Epson Matte paper have been less than 
spectacular.  Here is my question. 

After editing my image and saving it as a Tiff, am I supposed to change 
my working space (color profile) to Gray Gamma 2.2 before I print.  
Since I do not have an Eye-One spectrometer, I was not sure what to do 
with the image before printing.

QTR included two pre-made icc profiles, one for glossy and one for 
matte papers, but I was not sure if they were for soft-proffing only or 
to be used in the final file for those of us who do not own a 
spectrometer. 

My results with both Gray Gamma 2.2 and the QTR icc were very similar.  

Any advice would be appreciated.