While in theory it would be pretty interesting to take the harder teacher, learn more and have a better understanding.. For the sake of GPA and free time, i would take the easier one and put more than necessary effort into it. Im sure the prof could answer any questions you might have.
The DAT really tests general concepts and then a select few of reactions/mechanisms. Orgo is surely important and takes 30 minutes of the 90 for natural sciences. But you can do well even after having done poorly in class if you know how to study for standardized exams. Also as an afterthought, if youre more interested in learning orgo 2 for the good grade & the DAT, i would reccomend buying ORGOMANS Destroyer ahead of time, so you will have it in advance of studying for the DAT. This way, you can see what you need to know/ pay extra attention to during orgo2, and even ask professors help for questions you dont understand.
Dental Admission Test----
Survey of Natural Sciences 90 minutes
Perceptual Ability Test 60 minutes
Reading Comprehension Test 60 minutes
Quantitative Reasoning Test 45 minutes