Digital BW, The Print

Hello all.  I'm new to the forum.  I've been working out my methods
of 
B&W printing on an Epson 780 using the MIS UT2 inkset.  I have been 
using/experimenting with the Paul Roarke curves.  When printing a
step 
wedge, my max black happens around 94%.  

So in order to keep certain dark areas of an image from blocking up,
I 
can use either the levels dialogue or the curves dialogue and adjust
my 
output down appropriately.  Should this be done before or after 
applying the curves or do these curves correct this?  If using the 
curves dialogue would I apply it to the RGB curve - as I understand 
this may mess everything up.

Thanks,
Earl