Digital BW, The Print

I just got a new Epson 1280 which I will use primarily for Black & 
White. I think I'd like to run a few sheets through with the color 
first to see how it compares with my R1800.  If I do so, and put my 
new MIS UT-2 inks in afterwards, is there much ink wasted when purging 
out the old color inks;  and, is there any feasible way to store the 
color carts to reuse again down the road in case of a color 
emergency?  

Thanks in advance for assistance.

Dave