In my opinion one competent adult can handle 99% of BCIs out there. Standard ideals say that there needs to be one person for every 6 feet of snake. From my perspective that depends on the individual handler, and the snake itself. I have felt very comfortable holding 10+ foot burms by myself in the past. However, if there is any question as to the snakes temperament, it is always safe to abide by the 6' rule. For BCIs I would say that you are safe to handle them solo. That being said, I am sure there are one or two large and angry boas out there that might necessitate two people, but I am yet to come across one.