[InFlight]

I would personally think a poster size board in the shop area with a matrix of the students and certifications might be easier to maintain, and more importantly visible.

The lead shop mentor could be responsible for all approvals (initial or stamp) . This would also give visibility to students that would benefit from some time be checked out on additional tools.

In my view; it's all about giving the students to opportunity to broaden their skill set in a safe manner.