It may seem strange, but the way a man acts around his friends, towards waitstaff, or around strangers can be as much a part of flirting as the fabled "line."
Speak to the owner of the catering company or director of catering to ensure all waitstaff serving alcohol are briefed on sensible alcohol serving procedures.
If there are more customers than the waitstaff can handle, then they will end up leaving - so you have to maintain a balance of several different factors.
Customers come into the restaurant, waitstaff takes care of their orders, the chefs cook the dishes, and money comes in.
You'll want to find a place with soft lighting, well-dressed waitstaff, private tables and exquisite food.