That is an interesting approach - i had not encountered it before. I would think that at least 'roughing out' your notes before class might be helpful. I don't take shorthand. Me mum was a legal secretary, and on numerous occasions i was in her office (whilest i was in high school), and heard her and her mates trying to 're-construct' depositions that had been taken 2 or 3 years before. Depositions are written statements by witnesses, which are admissible in court and become part of the legal record. I was amazed to hear these 'professional' secretaries reading shorthand notes of a deposition, and coming up with 8 or 10 (or more) versions that differed very substantially in fact from each other. I decided that if there was that much variation when professionals did it, i would stick to tape recording - which i did. I taped nearly all my classes when i was working on my MSEE degree [master of science, electrical engineering]. I would leave lots of blank space in my notes [using a loose leaf note book - so i could put in extra pages when needed], and fill them in when i played the tape back over the next few days. Today, of course, you can get completely electronic recorders, which are much better quality. Either way, you would get 'more complete' notes of the class, than only taking them 'live' whilest sitting in the class.
I would also keep track of the amount of time that an instructor would spend on a particular topic, and how much work they did - did they just talk about it, draw something on the board, draw something really complicated, give the students pre-prepared hand-outs, have viewgraphs [with overhead projector] made up ahead of time... Each of these was more work for the instructor, and showed that they thought that this particular topic was more important. I would add up the number of minutes at each 'work level' that the instructor had put in on a particular topic [multiplied by the 'work level']. The total would give a rough measure of the importance of that topic to the course (in the instructor's mind). I found that this indicated fairly accurately the liklihood of a question on that topic appearing on the next exam. Best of luck!!