We are having a very large wedding 560 people and we are doing an open bar but we are just not sure how much of each mixer to buy we are having pepsi, 7up, cranberry, orange, pineapple, club soda, tonic, grenadine, lime juce, lemonade, and probably a few more that I am forgetting does anyone have any idea of how much of each of those to buy? Any help is greatly appreciated. thanks