In really basic terms, N +/- processing is more directed at sheet film development, whereby you control the density of the highlights by development duration on individual sheets.

Whilst this is somewhat useful to roll film development, it is less applicable as there are multiple images involved, making specific development changes difficult if these images have different requirements.

If you haven't already read up on it, I would suggest researching divided development and/or semi-stand development. IMO, much more useful for roll film applications (see here for some information and examples)