Well I'm not JD, but I also do it manually (and get within ball park in about 20 seconds unless its a big file).
I have a few points on my blog (search on epson) but:
- scan neg as positve (this causes hassles with my Nikon SA-21 finding the locations)
- assign (NOT convert) profile to scanners appropriate profile (*)
- invert
- set each of black and white end of R G and B channels independently
- perhaps tweak a curve of one or other if shot in the wrong colour temperature light
- done
the profile will be the critical step, and depending on scanner will vary. For example I have my Nikonscan set to be bruce RGB, I have my Epson set for doing nothing and so I assign the Epson 4990 TPU profile (if using my 4990)
I have always found that the auto settings clip more that is really signal than I like and I prefer to use curves to settle this than hard clipping. Unless you like that look....