Wow Boris, wonderful! I think that teaching is always a great experience and, despite the fact I did myself some “introduction lessons to darktable” in my local photoclub, I would really love to be good enough in doing what you did.
BTW I’ve always appreciated your videos, and I would kill 
to be part of that class you had. Because, as you mentioned, the manual is not enough to give an holistic view of what the process (and possibilities) are, and the videos alone can’t do it either. Have you considered online classes? 