My hat is off to you!! I would never have pulled that off!! The best tip you mentioned? STAY AWAY FROM GIFT SHOPS! LOL, I have trouble getting my family of 4 out of the gift shops!
Plan one dinner a day for the group and let them do what they want the rest of the time. This is what has worked when we went with 11 people. Sometimes we were all together and most time people broke into groups.