best to try first day you can book and then as others as have stated try every day in the early mornings and when you check it automatically checks hour before and after time you request. I have gotten in checking on line later in the evening also.
It's like the disney gods have bestoyed upon us a slew of open ressies in dec for le cellier. There was atleast one open every night of our stay. Can I get an AMEN?! LOL!