Rafal, regarding what CI to target for N-, N+ etc, everyone prints differently and has their own preferences. Some people prefer softer negatives, some prefer less or more contrast in the negative depending on their chosen papers and preferred techniques, some people prefer a thicker negative (ie more exposure) etc. To that end, I'm not convinced there are better ballpark starting points than some of the target densities in Adams. They're as good as anything else. Perhaps start there, make some test images and print them so you can figure it out for yourself based on your own printing. There's nothing like doing a lot of testing and dialing in the process only to find out during printing you're not getting the negatives you thought you were getting, or thought you wanted.
I have to also say I'm generally not a fan of metrics such as CI, Gamma etc. I look at them as "nice to know" results after plotting the curves, but it's really the full H&D curve that tells me what I need to know, not contrast index - particularly when it comes to N minus territory.