I think it really depends on your comfort level, and what you cook with.
We are a team of 2, myself and my wife. We cook on WSM's, so don't need to do shifts tending the fire. I do most of the prep and cooking, my wife assists, and does some of the finer details in arranging our final boxes.
I've seen lots of teams of 1, and some of up to 8
I think you have to try it a few times and see what works for you