
Based on last year, start watching around August as there was one round of codes that came out mid-August for stays including December dates, then another round of codes came out around September 27 that also included December stays:
Check ins between 9/30/07-12/23/07 package discounts for Disney Rewards® Visa® Cardholders became available on 8/13/07, exp 9/26/07
Check ins between 9/30/07-12/23/07 Annual Passholder room-only rates became available on 8/15/07, exp 12/23/07
Check ins between 9/30/07-12/23/07 package discounts for general public became available on 8/16/07, exp 9/26/07
Check ins between 9/30/07-12/23/07 Florida resident room-only rates became available on 8/16/07, exp 12/23/07
Check ins between 10/21/07-12/15/07 Annual Passholder room-only rates with dining gift card became available on 8/15/07, exp 12/15/07
Check ins between 10/21/07-12/15/07 Florida resident room-only rates with dining gift card became available on 8/16/07, exp 12/15/07
Check ins between 10/21/07-12/15/07 Military room-only rates 9/5/07
Check ins between 10/21/07-12/15/07 package discount for Disney Rewards® Visa® Cardholders became available on 9/27/07, exp 10/20/07
Check ins between 10/21/07-12/23/07 room-only discount for general public became available on 9/27/07, exp 10/20/07
Check ins between 10/21/07-12/23/07 package discounts for general public became available on 9/27/07, exp 10/20/07
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I don't know what rate you have now at the WL, but maybe a CR Wing room might be close with a good code. But remember when and if those codes come out again this year, your WL rate would also probably go down, and then it will be hard to leave that res!