Yes, 7 days, whether it is your home resort at the 11 month window, or a non-home resort at the 7 month window. If you need 10 days, start by booking the first 7 as early as possible, and then modify to add the additional days.
If booked at the 11 month window in your home resort, you're almost guaranteed to be able to modify to add the extra days unless a room is scheduled to be taken out of service for maintenance or remodeling, or possibly if it is bumping into somebody's guaranteed week contract reservation.
If booked at the 7 month window, even if you're able to grab the first 7 days, there is no guarantee to be able to modify & add a few more days. You could easily bump into somebody else's home resort reservation.