Anything in print relating to masking is going to be of generic value and not up to date with present materials. But lots of those old manuals
do provide hints about equipment etc. Some of the most complete tutorials were by Bob Pace, though these were gear to either dye transfer printing or Cibachrome. I'm not aware of anything that is very good when it comes to understanding supplemental masking to color neg films, since most people didn't bother in that case. Maybe I'm one of a handful of people who does. The trick is to acquire a basic setup of the tools themselves, particularly a film punch and matching contact frame, which can be used for all kinds of masking techniques. But yeah, there's a reason so many Photoshop controls were named for something done by manually with film previously. And in some cases, I think film still does it better, though not necessarily faster. Anyway, masking can be fun, and be either as simple or involved as you care to
make it.