We've gone twice between Christmas and New Years and agree with Grumpy92 that it is important to call right away for Christmas Eve, Day and NYE. We did do the CP dinner package on Christmas Day both times. Magical. We also did Hoopde Doo on NYE as we didn't want to go in a park. Booked that farther out, too.
For PSs the rest of the week, I just made one call at the end of the booking windows...still 60 and 120 those years. I dodn't think many people are as obsessive about planning as those of us here. Got everything I wanted both trips.