I thought I was just making a few burgers but ended up making close to 30 sliders of varying sizes. It was a real workout and the heat was unforgiving. We tested burgers without any seasoning, save salt on the patty and butter on the toasted buns. And since it was my lunchtime I had them pick up a Vidalia onion so I could make one of my favorites - the Oklahoma Onion-Fried burger. They were a hit, though some complained that they were 'greasy' (which they are of course - that's why they are so good.)
Hopefully I changed their minds. They plan to replace their outdoor flame grills with rented flattops temporarily. Let's see what happens when someone complains that they want their burger 'flame-grilled' at the next 800 person Gracie Mansion cookout. I may take a guest spin on the griddle at the next cookout too..