I'd say you're on the right track.
You don't need a digital proof every step of the way. Only to get you started.
Once you have the color(s) the way you want them, they aren't likely to change much.
Besides, as most people who work on negatives, you'll probably start to see in reverse, anyway. ;)
Shoot, I have done it. Similar anyway. 30 years ago... I must have had boundless energy because I also made copy shots of the finished print to use in a slide show...
I think I used a sheet of plastic over the 35mm negative and colored in the complementary color with an ordinary felt pen... then I printed the black and white negative to color paper...
Yellow painting made a Blue raincoat... Blue paint made a yellow campfire... The red made kind of teal trees...
eddie + randy, thanks !
and bill, those are pretty cool .
thanks for digging them up :)