WDWalways....
Looking at the numerous vacation visits under your signature, I can't really see that one use month will be much better than another for you. You seem to vacation at various times of the year.....so since you don't usually vacation at a particular time of the year, you can't really pick a use month that will help you out of last minute cancellations.
If you vacationed during the summer each year, then you would want to avoid a mid-summer or end of summer use year because you would have so little time to use any cancelled points.
Hopefully, I haven't confused you. I think what I'm trying to say is that I think it doesn't matter much what your use month is if your vacation pattern is at various times of the year. For us, we go often in the summer so our February use month is fine. However, it won't be so good if we later on decide to go mainly on December/January trips.