One of the things they teach you, somewhere, when you are trying to debug something is to only change one variable at a time. If you change two things and the problem is fixed, then you don't know what fixed it. Both things, one of the things, or could it have been even more complex than that? Those two things effected some other variable that you weren't even aware of.
Anyway, I did make that cardinal mistake because before the printer really began performing I changed several things:
1) Pulled some cat hair from underneath the inkhead with a q-tip.
2) Had recently changed the black ink to Eboni.
3) And had re-aligned the print head (actually only the color head).
So now I don't know what fixed the various problems I was having with micro-banding or the slight touch of graininess in certain areas - but they are gone.
Also - with this paper / printer / ink combination - removing the "pizza - ejector" wheels is an absolute must. Since you are only doing one sheet at a time -- no way are you going to be stacking these things up - you don't need to risk the chance of the wheels tracking little marks across the face of the print. Just one more thing that can't go wrong if the things are gone.