Piezography WNK7 cart/ink setup

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!

You may leave the printer in its current black mode (Photo Black) and simply put matte black ink into the PK cart which is marked only as “black”. Make a notation on the cart so that you know what’s in there! While the Epson driver minds whether you are in PK or MK mode, QTR will not restrict you.