You can make them up to 180 days in advance of your arrival. This calculator is handy for the exact dates(see site below). You can book the reservations for the length of your stay, for example, for Dec 7th arrival, you can start booking on 6/10/08, and book your ADRs for each night of your stay then. Good luck, hope you get what you want! http://pscalculator.net/pscalc.php