I was in the same situation as you about 4 weeks ago. I took the DAT last week and managed to get a 27 on OC so I'll just tell you what worked for me. After I finished going over Chad's videos I spent about 2 hours going over every single reaction on the Destroyer roadmap, only looking at the reagent and trying to predict the product. After going over the roadmap and spending every day practicing DAT Destroyer questions, I naturally began remembering what each reagent does. DAT Bootcamp also does a great job covering most (if not all) of the questions that the actual DAT will have, as well as thoroughly explaining each answer.
Also, don't lose confidence just because you're getting destroyed by DAT Destroyer- that's what it's meant to do. I was only getting ~50% right when I first went over it (I went over it twice). The second time around I was scoring much better because I was actually learning from my mistakes. Also, the simple fact that you understood everything from Chad means you're on a good track. Just remember to go over all your wrong answers and rewatch some Chad lectures if you need to. I found that watching a lecture immediately after getting a question wrong is much more helpful in getting the material to stick inside your head, rather than just watching it and taking notes from it.
Good luck!
