I agree, take it right after Ochem or even biochem, you'll be glad you did. I graduated in August and just about had to relearn everything again.
I used the kaplan blue book, flashcard exchange, crack dat (dont get the science version it SUCKS because i kept on scoring a 15 on it because the questions were horrible, get crack PAT and MATH if anything, its excellent!)I did not use chads videos. My weak point was always gchem. I studied for 3 months anywhere from 2-10 hours a day. For gchem I used chemguy.com. You pay like 10 dollars and get access to hundreds of very good chemistry videos (basically like a lecture). This guy has an excellent way of teaching it to you. And he's kind of entertaining LOL. You may have not been weak in that area, but that's what I used.
I took my DAT yesterday and scored 24 PAT/24 TS/23 AA