I can’t help you out with negadoctor, but if you want to try RawTherapee’s film negative tool, I can definitely provide you with assistance for that including some currently in-development test code ( Film Negative - Improper assumption of mapping between raw values and transmission coefficient · Issue #7063 · Beep6581/RawTherapee · GitHub )
You may also want to read the discussion at Digitizing film using DSLR and RGB LED lights regarding initial capture of the negatives. If you can’t do individual monochromatic captures, having a backlight with R, G, and B all being strongly monochromatic (such as an OLED display) is highly useful, especially if you can adjust the backlight balance so that the red, green, and blue channels are equal after filtering by the orange mask.
Note that I’ve been focusing on attempting to recover original scene colors accurately and not on emulating print behaviors.
I’ve found that what works for me is I USUALLY have one or two unexposed frames somewhere, or a bit of unexposed film at the end of a roll. I can digitize this and as long as my backlight and camera settings don’t change, that mask sample is valid for the whole roll and even other rolls of the same film. Looks like you’re using a Nikon ES-2, I’m using JJC’s knockoff of the same product. So no mask in the borders of a frame, but I can usually find at least one frame or partial frame that is completely unexposed.
I saw your Kodak Gold post. I actually have a DCP profile for Kodak Gold 200 that can be used with RawTherapee’s color pipeline and it works REALLY well, even for ancient negatives such as Gold 400 that was shot and developed 25 years ago. However unlike your goals with doing things that were shot recently on new film to get an “analog” effect, my goals have been to minimize “analog” effects and recover original scene color as well as I can.