Many thanks for the wealth of information, Paul. Much appreciated. The cartridge configuration you describe looks like a good way to go. My ears really perked up when you mentioned Arches, since I have begun experimenting with hot press Aquarelle, which even with the standard Eboni-6 inks from MIS looks pretty decent. Iʻll look forward to trying out the C6c base with the two-positions for MK ink.
Congratulations on the acquisition of the 9880. Iʻm jealous.