Digital BW, The Print

I took the plunge yesterday and bought an R2400. As advertised, I get
neutral toned B&W out of the box. No more magenta & green casts that I
got from the R800 (which I still have). That's a BIG improvement.
There also appears to be more detail, particularly in shadows. 

So far I've only printed on Epson Premium Luster using the PK ink. I
chose PK because I thought it would give me the most flexibility in
B&W and color; but of course it limits me, so I have two beginner
questions for those who have worked out their routines with the K3 inks: 

1. Do you routinely use PK ink for B&W or have you settled on MK instead?

2. If you are using PK, what paper are you routinely using with PK ink
for B&W images? 

I don't recall 2400 users on this list switching inks often, although
if someone does, I'd certainly like to hear your thoughts. 

Since I still have my R800, I have some flexibility. I can use it for
photo black color printing if it looks as if MK ink is the best
option. I'm not inclined to use it for b&w because of the color casts.

(I assume at some point I'm going to try BO in some printer but not
right away.)