Thats great, I am myself in a big dilemma, what time would be perfect. I am going to take a date for first week of sept, and will have to take date in march start, considering all slots in bay area get taken up very quickly!
I am in the New York area and here, it is said, that we need to book slots atleast 2 months in advance to be sure of the time/date that we want.
So,it wuld be a good idea for you too, to book early and then prepare yourself for that time.
I know that some people may have found this post of mine very trivial (how does the time matter???!!!) but, this did AFFECT me largely since being a strict non-morning person, I took the test at 8 AM only to realize that I had not yet 'woken' up fully