If thepark opens at 9, you can try for 8 am seating and be at rope drop by 9. If it's EE, I would do 2 hours in the park first and try for a 10 am seating. However, you have to remember that by the time they check your times (and find them unavailable) you will have lost all the other time slots too. I would just say earliest possible time (8) or latest possible time (10:30) and see what you get.
Got to the park, took advantage of the rides, for awhile, and then had a 9:55 reservation. After breakfast, stayed till it got crowded, and moved on to MGM. Worked out great.
I think you should just go for whatever time you can get. We had an 8:15 PS. We arrived at 8 am and got in -- they seated us right away, and we were there for the rope drop at 9 am, and had all of Fantasyland done by 10.