There are a lot less villas at GCV so plan to rent from an owner at least by 9 months out. You may pay a premium for points since you will most likeyl need to book before the 7 month window.
it would be best to go to the rent/trade board and look for someone who has GC as their home resort, they can book 11 months out. Although, I did hear on the boards that someone was able to get one at 2 months out with no problems. It just depends on the time of year I guess.
Yes, different people I am sure have different processes. Just go on to one of their posts and ask your questions.