I booked at 180 days out for my December trip and both of those were available on several dates had I wanted them. It really depends on how many other people want the same thing on the same day! Are you flexible in which day of the trip you'll do this? If so, I'd go for the latest possible date first as there are likely fewer people able to book that date (assuming you're staying on site and can book ADRs for length of stay).