Digital BW, The Print

I asked this question once before with no response, so I'll ask again :)
I'm currently printing with the MIS-FS quad inkset on an Epson 1160.
The resulting prints are very nice, but I would prefer a slightly cooler
look.  Is there a way to cool the prints by adding a bit of blue ink to
one or more of the 4 standard gray inks?  I'm using a CIS with 4 oz.
bottles.  I seem to remember Jerry Olson cooling his prints this way a
while back?  Thanks in advance for any guidance that anybody can
provide. --- John.