For the 8 channel P2/PiezoDN setup, MK goes in the Black position, and PK goes in the Yellow position. The HD blacks are a new option, though the positions are the same.
As for the labeling, I agree it is a bit confusing, but the blacks are the same for all the K7/K6 inksets, regardless of tone. Just be sure you know which is Matte and which is Photo. I’m using the K7-Carbon inkset, and my blacks are labeled the same as yours:
- Matte Black is Neutral Shade 1, and goes in the Black position.
- Photo Black is Warm-Neutral Shade 1, and goes in the Yellow position.