Digital BW, The Print

I am new to digital printing and am experimenting with QTR with full 
Ultrachrome inkset on a 2200 and MAC OS10.3.7. My prints are neutral
but 
I'm trying for a richer black. I'm printing on EEM and waiting for a
package of 
Moab Entrada to arrive. I'm pushing the contrast with PS curves about
as 
much as I'm comfortable with. I've been using a cold/warm range of 
85/15 
(too cold) to 70/30 with ink level at +25%. I have a cartridge of
Eboni ink (UT7-
T038) thinking I would substitute this for one of the UC black or
grey 
cartridges. Is anyone using a setup like this? Which substitution is 
recommended? Anyother ideas about what to tweek? Thanks for any help.