1. If you make a "Both Parks" reservation, it only counts as 1.
2. You can only book 30 Days in advance. They will put a line through the 31st Day, but it will open up 30 days before that day.
3. You can make same day reservations if they still have availability.
4. After the conclusion of your reserved day, i.e. Midnight, you will again be able to make another reservation. Some have reported that they had it open earlier in the day, but that seems to be the exception.