So my wedding is this Saturday, and we had the final meeting with the caterer last night. And it occurred to me that I have no idea how to tip them. We are having a buffet dinner, and we will have 4 waitstaff/kitchen staff (one of whom is the owner of the restaurant who is catering our reception), and a bartender. It seems like the standard restaurant 15 - 20% of the bill, which would come out to something like $200 per staff person including the owner, is too much (and is complicated by the fact that the bartender will be serving drinks that were purchased elsewhere), but what would be appropriate?