I paused a lot to take notes. I went through the first ten G-chem videos without taking notes and was understanding everything well (he does an excellent job of explaining everything). However, once I got to the later videos, I was beginning to forget some of the concepts in the earlier ones. Because I hadn't taken notes, I had to watch an entire video if I had forgotten one part of a concept. So the second time through the G-Chem (and through all of the O-chem) I took notes. It takes a little longer initially, but will save you time when you want to review.
I haven't taken the DAT yet (I take it this Saturday), but from what I hear Chad + Destroyer = 20+ (God I hope this is true...)