Don, On the old OHP I use a QTR profile called RR4000-UCmk7-OHP-Pd that is attached to this message. This profile uses matte black and light black ink plus a lesser amount of all the others. It makes fine negs for printing on palladium. As you can see, the default ink limit is only set at 44, so it could be dialed up much higher (I did it once by accident) and you will get a much, much denser neg. I don't know how high you can go before the ink begins to run, but the density is well over 4.0 in the UV.
To try out the Ultra OHP I decided it needed a slightly different profile, so I redid it and while I was at it I dialed the matte black ink way down, kept the light black about where it was, and increased all the others. This profile is attached and is called RR4000-UCmk7-OHPU-Pd. To my eye I cannot see any quality difference, due to either the lower usage of dark black, nor to usage of Ultra OHP.
I really wonder if the fear of black inks is not a red herring? Certainly you get inferior negs when you print with only matte black and light black ink. But I bet the printer would also print poor negs if you only used Cyan and light Cyan (never done the experiment, though). My guess is that using all possible inks leads to smoother tones, but no one ink is better or worse than any other. Anyone have any hard evidence to the contrary?? Cheers, Ron-san