If you are willing to pay rack rate at that resort, then make the reservation now. Already having a reservation does not give you an advantage when AP rates come out. It can actually hurt because if they see most of the rooms are already booked up for your dates, they will not make an AP rate available for those dates. If you are not willing to pack rack rate, then make a reservation at a resort you would pay rack rate at as a backup in case you do not get the AP rate you want.