Hi dwelty,
I checked my palm pilot (I love that thing) and our NE break was a week after Easter in 2007 so I suspect that helped.
I also recall that I found someone on the rent trade board who was willing to swap his HH points for our BC or BW points. We would have made equivalent reservations for each other at 11 months and paid the difference in cash, but since I had no trouble booking it at 7 months, I didn't need his help. So that's a way to possibly do the reservation earlier than 7 months.