If you want to book your whole stay at one time, yes....11 months prior to check OUT date because then you'll be within the 11 month window on all your dates.
If you're looking for a particularly hard to get room (GV, boardwalk view at BWV, anything at an Epcot resort during Food and Wine, and probably the AKV Concierge), or you just want to really mak sure you get the dates you want, you can book day by day. You book your check IN day 11 months prior, then the next day 11 months prior, until you hit your check OUT day. For example:
Check in day is April 8th....you can book that night on May 9th.
Next day is April 9th...you can book that night on May 10th.
Next day is April 10th...you can book that night on May 11th
Etc until you hit your last night.
Then ask MS to link all the ressies together.