As for the self-defense classes, that is a major pet peeve for me. They take money but actually end up with the student worse off because now they think they know something.
AMEN. But, SD classes that taught...what, maybe 1 technique an hour...wouldn't sell. So, people teaching that stuff try and cram as much stuff in as possible without any meaningful drill time. I had that complaint with Guro Presas in his later seminars. Too much stuff to get a good grasp. I'd rather learn 2 or 3 things over a couple of hours and come away really knowing them.

I'll come back later...but as a question: how long do you think it takes to 'learn' a new chin na move? Not 'master' whatever that means but learn it well enough to drill it later w/o help from the person that taught it to you. I said an hour above but maybe less could be appropriate.