For a full flight, the number would be dependant on whether it's domestic, or international. I only worked with domestic flights back when I was a ramper, but I seem to remember that it was only about 4-5 LD2's for a 767. This out of 32 positions for a 767-300. We were only alotted 16 for cargo, which, I believe, was just in case baggage was more than intended.
Two all beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun.