August or September would work well for you - since you would usually have plenty of time to reuse (or bank) any points returned from a cancellation. I would advise against a February or March Use Year for travels in Sept/Oct/Dec.
IMO, Use Year is an overrated concern unless you are prone to frequent cancellation. I would concentrate more on finding a contract that meets your needs (resort, number of points) than worrying about a specific Use Year.