[Taylor]

As the only full-time adult working with my team, and 50 students on our current year's roster, I can say there's no such thing as too little space or not enough adult help.
Be creative in how you use the veteran members of your team. One of the team mottos is "your second season as a CyberCard is your first season as a Mentor" - allow experienced students to take on leadership roles, design activities, generate ideas.
As Alan said, parents are a valuable resource - don't overlook them.
An ongoing conversation I've had with several of my FriendsWithRobots revolves around the idea that some people need the team more than the team needs these people. These fine folks will fall through if membership consideration is based on interviews, applications, or grade requirements.