Definitely make your reservation at 11 months out then call at 7 months to change over. IF you have enough points, make a duplicate reservation until you get to the last day then you can cancel SSR. If you don't have enough points, just call 7 months from the last day and change over, if what you want isn't available, wait list it. You coulod also change day by day but might end up with two separate reservations and thus having to move. There are actually several variations on these thems depending on your sense of adventure, number of points you have and how important a given option is to the member.