P2 inks in 3880

I’m ready to load my P2 inkset. Couple of questions. 1) I guessing I should put some Epson ink into my PK cart (since the PK ink goes in the yellow) and then manually select MK for the black? Or should I also put Piezo MK ink in the PK cart? 2) Will the machine still do it’s 6 month black ink change or is the unused channel going to be totally dormant? Should I periodically use the ink in the PK lines so it doesn’t get stale?