If you want to make a reservation for November 1 at a resort you "own," you may make that reservation 11 months before November 1, as long as the points you need for that reservation will be accessible in your account when they are needed (on November 1). If you have a June use year, you can still call in January, when you may have zero points accessible immediately 'cause you've used all your points in the present year, and you can make your reservation with points that will become available for you to use on June 1. For an October reservation, you can call in December, to use any points that will be available to you the next October. No one can get a reservation more than 11 months prior to the day they will "check out" from that reservation - so you are not behind anybody.
Your use year really doesn't matter for any practical purposes other than for banking and borrowing. BUT - If you always travel at a certain time of year, you would not want to have a use year where your travel dates fall within the last 4 months of the use year - because if you have to cancel your travel plans, you will not have time to bank those points. And there are restrictions on what you can do with those points that have gone past banking periods.