The usual booking window applies. I'm not going until the end of September, so I don't have to call until the end of February. Good thing, considering what happened on the 8th!
Starting Feb 22, you can use non-BLT points to book BLT, non-SSR points to book THV, subject to the usual 7-month window. Even owners have to wait until Feb 22 if they want to use something other than home resort points to make a reservation.