[GeeTwo]

You've obviously taken the first step - recognizing that this IS a different situation that may call for a new solution, but you're doing research to see what has already taken place. Sounds like an engineer..

While every team has different dynamics, the great majority seem to promote peer mentorship, that is, veterans working with rookies in pairs or other work groups where the teaching aspect of the relationship is as important (or more important) than the leadership aspect. This is a great thing to do, but sometimes it can make it more difficult to make the transition from high school senior to college mentor.

If your team has taken other "junior mentors" recently, follow their example. I'm going to assume for the rest of this that you're the first, at least in a while.
Consider what your teams "mentor rules" are. In particular, consider how heavily and in what roles they participate in different processes. If a certain role is "taboo" for mentors, follow that taboo. For other roles, consider where along the continuum between student and mentor you think you should be, and make a list. Most importantly: Discuss this separately* with your team's coach/lead mentors and your team's student leaders BEFORE build season starts (You've got a week and a half). Adjust as necessary so that you and the other team leaders have an idea what to expect from each other.

* Not necessarily individually, but have a session with mentors and no students, and one with you and students, but no other mentors to reduce the chance of people "holding back" their concerns.