Digital BW, The Print

HELP!! I must be getting old but I can't preview the changes I make to 
a custom dot gain curve. I start with a 21 step grayscale and apply one 
on Paul's curves. I then print the curve. I then go into CS2 and 
through assign profile I check don't color manage. I then go into Color 
Settings and in Working Space Gray I select Custom Dot Gain. The Curve 
comes up but as I make changes it has no effect of the grayscale on the 
monitor. I have Preview checked in the Color Setting menu. I have tried 
flattening the scale and the curve, converted from RGB to Grayscale, 
making the background active - - - still no effect. I have done this 
before but for some reason I continue to have difficulty with this. 
Thanks in advance.