Digital BW, The Print

Has anyone experimented with the PiezoTones by using the Carbon Sepia
ink with the Warm Neutral in the same printer but in different
positions? I am about to reorder ink and I am thinking about buying
Carbon Sepia as my dark position ink and using it with the Warm
Neutral in all the other positions. So far so good with the warm
neutrals so I do not want to mess things up. I understand that they
are intermixable, but is there enough of a difference between these
two colors for this to work? I want my darks warmer for a duotone
effect.

Mike