The use year issue is one of what happens if you have to cancel. You have until eighth month of use year to bank all your current use year points into the next year. If you travel at end of your use year, like Nov if Dec use year, and have to cancel a couple months before the trip you will be beyond the banking deadline and unable to bank points and they will expire that Nov 30 and thus you are likley to lose them if you cannot go before end of use year. If you book a date that is shortly after your use year begins, like Dec or Jan if you have Dec use year and then later have to cancel, you will still have a long time to either use the points or bank them.
Thus, if usual time to go is Nov, Dec is the worst year you could have. If usual time is Dec then Dec is the best use year to have. In other words, it is best to have a use year that begins the same month as, or shortly before, you usually go to WDW. Nevertheless even a use year that begins four months before usual travel time as suggested as one of the choices above above is fine.