Depends how flexible you are for the discussion sections. It seems like the most popular discussion section is TuTh 1-2 pm followed by 2-3 pm. If you can only attend these two sections you should phase 1 the class. Otherwise if you don't mind having a 8-9 am section go ahead and phase 2.
No guarantees though... they don't know who the prof is going to be yet but if it's a really good prof then don't be surprised if a mass of people suddenly enroll.