I would even try a few days before you go. People (including myself) have reported several tables and times opening up when they had previously been told that the times they wanted were not available. Hope you get what you need!
Don't know exactly the dates you're going but I will be cancelling a PS for CM dinner at 6:15 PM on Tuesday 6/17. Aslo just cancelled two CM breakfast PS one for 6/16 and one for 6/18.