I would imagine the tip thing might be a little difficult unless you know right now exactly what you're going to eat. You could look at the menus and get a rough idea but when you get there you don't know if you're going to order apps and desserts for sure, do you? What you will be drinking?

The only ones that will be easy are the meals that are one set price, like CRT.
Do you already have a plan for who you are paying for? Like who will be on your checks? Since you have such a large group I didn't know if you had any "deals" made with your family members.
Not knowing drove me crazy so I made the deal with my mom that I would treat her for the entire trip, airfare, food, hotel, tickets for everything and the extra stuff, firework cruise, cabana if she would just pay the tips as we go along. I have no problem with pre-paid expenses but once you get into the ??? money I fall apart. I told her that she would probably have close to $1000 in tips. I figured $100 for tips/day and then if it's a bit more she won't be shocked and if it's less than she'll be pleasantly surprised. We'll have to see how close I end up being after the trip is done. I will have her keep track so that I can plan for my next trip better.