We own at AKL (2 contracts) and Poly, will be buying CCV.
Use year will likely be the same- there's no real reason to get a different one when buying direct. Keeping everything the same use year makes tracking things easier.
As for booking window, it's been said- you can only use the points for a given resort at that resort for the 11 month window. At 7 months you can use both. When you book a stay it will ask you which contract you want to use and only let you use the ones that are available at that booking window. At 11 months I can book AKL with 260 points or Poly with 60, but I can't use all 320 at one resort. At 7 months I can.
Your contract numbers will be the same, but with ".0, .1, .2..." tacked on the ends.