I should have Matte Black ink in the next day, and am looking forward to testing it out on some Fine Art papers in the 4800 - the first of which is Breathing Color's Elegance, a 310g 100% cotton fiber paper and is acid and lignin free. It looks to be a very nice paper, I have a handful of A3+ test sheets here waiting.

From the information on Breathing Color's site Epson's Watercolor Radiant White profile is worth a try with Matte black, and Premium Glossy with Photo Black. I'll be getting a custom profile made, but will do a test print today using Photo Black.

I'm also looking forward to checking out the black ink changeover process :)