Well... for me, in a two-screen subrun theater, I had 4 people, plus myself, behind the con counter (1 on each register, one pulling drinks for one till, one doing corn for both tills, and myself either pulling drinks or doing...whatever.) There were a couple of times we'd do that. I think we may have staffed 5 people behind the con counter, once or twice (usually by grabbing an employee there to see a movie and drafting them into temporary service). However, 3 or 4 behind con was pretty typical for Friday and Saturday nights, or for kiddie matinees on the weekend.