I'm saying by participation. Basically, enrollment doesn't work at all.
The Grand Island example is perfect. You have the highest enrollment, and you have no SRs or JRs on a team that needs 5 players.
I think some kind of formula that shows participation, with a weight associated with the upper classes, may make more sense. In theory, maybe the GI girls basketball team would end up being Class C or something? This probably wouldn't work any because of conferences and scheduling. But it's not working now either.