If I want to book my home resort at 11 months out...do I call 11 months out from the first day of my planned vacation or do I have to wait for the last day to be 11 months out?
Yes, you could call on 1/12/10 for a reservation for 12/12/10 for 7 nights. Then you would have to call the next day to add the 8th day of your reservation or wait 3 days to book the last 3 days all together.
If there is any confusion over this, it's probably because for the first 17 years or so of DVC, 11/7 month windows were based on check-out date. But a year or so ago, they changed the rules to base the 11/7 month window on check-in date.