My 4900 has PK and MK dead, possibly a ruined distributor where the channels meet to share the head.
But I haven't tried anything on it so far. In the past, helping some friends I had more luck getting rid of clogs by cleaning the suction tray instead of the actual head, but I digress.
100% carbon because I am thinking of this printer as a learning step for me now.
I'm currently looking for a larger printer as well and then, maybe, I'll explore a matte/glossy and warm/neutral setup.
thanks for all the input. I'll order the carts and in a few months I'll came back to bug you all a bit more.