We went through David's for our recent (first) rental. They didn't have a member with the points we needed (for a 2-bedroom villa at Wilderness Lodge) at the 11-month mark. Neither did DVC Rental Store. Both of them put me on their waiting lists, and within a week, David's had a new member join who had the necessary points, so we got the reservation we wanted, after all.
I should mention that both companies were courteous, patient, prompt and professional in their communications with me, and also very up-front about the fact that they didn't have a member that could satisfy our request at 11 months out. As such, they didn't try to create false expectations -- and by doing so, their professionalism exceeded my expectations!
I don't know your chances, but if your request can't be met at 11 months out, I would suggest asking to be put on the "waiting list." All it takes is a new DVC member listing their points with one of those companies for a "no" to become a "yes." Keep in mind, though, that because the Grand Floridian is the newest, hottest DVC property, it may be one of the toughest ones for which to get a point rental right now.