Two man with the same shift each night, or three shifts a night, rotating in an ordered schedule so you get a different shift depending on the night would be good. Just as an OOC that relates to IC knowledge; dad did paratrooper and ranger training, apparently that's one of the best ways to do watch with limited groups. The shit he randomly taught me... anyways, two men per shift twice a night or one man per shift three times a night is a good way to go.