As with any "what are my chances" question, the real answer can only be provided by MS when you call to make the reservation.
In the case of GVs at OKW, there are a total of 27 at the resort. There are times when there will be availability within 7 months and times when nothing is available. Sometimes it is dependent on someone cancelling at the last moment to create the availability. You should have no problem reserving a GV at OKW 11 months ahead.
As suggested, if you can, have an OKW owner make the reservation for you 11 months ahead or find an owner to transfer the OKW points into your account so you can make the reservation yourself at 11 months using those points.