I am getting started with loading up new carts and inks in a 9800 with the WNK7 inkset (matte only). I am confused as to which cart is the appropriate cart for the Shade#1 Matte Black INK. Do I use the Matte Black cartridge, or the Black cartridge? THe printer is currently set up with Photo Black and I plan to go straight to an Initial Fill to purge the Epson color inks and fill with the WNK7 matte inkset. Advice is appreciated!