Digital BW, The Print

> I have a Sypder2 for calibrating my Apple LCD, 
> I then print an image on my Epson 2400 with an ABW ...

The Epson "Advanced B&W" is not a color managed system.  

> ... and change, by eyeball, my "color settings" custom
> dot gain curve to match the LCD 21 step curve image.

This is the step we're trying to get away from by using the color managed
("CM") workflows.  A perfect custom dot gain curve can be very good, but
most of us would rather not have to do this. 

>  I always seem to be off just slightly
> on the range from about 80 to 100% settings.

I've never seen a perfect system, but the CM approaches are better than my
custom curves.

Paul
www.PaulRoark.com