QTR-Quadtone RIP

Hi:

I have both an Epson 4000 and a 2200.  I am trying to set up a
Selenium toned QTR profile for both printers using Epson Premium
Luster paper.  I have gone through many iterations and keep having the
curve at the shadow end have minimal separation. I scan the 21 step in
using an Epson 3200 scanned as a 16 bit at 1200 dpi and I convert to
Lab color.  I can get the darkest black to an L of 6, but the next 4
steps up are 6, 7 and 8 and the next step is 10.  So I am getting
minimal separation in the shadows.  I have bumped the gamma up and
down, I have done black boost from 0 to 100, I have tried changing the
toner curves and all come out with minimal separation in the shadows.  

Has anyone set up a good cold tone selenium toned curve that they
would be willing to share?  

Thanks for any help.

Mike