If you look at iNat observations as a whole, for submissions (after casual grades), the bulk of species are likely in the macro range.
And if you look for maximizing interest in a group of young students, the greater the possibility of discovering new (to them) species, the greater the potential for success. Macro-centric observations maximize the potential discovery per square meter. In most cases, minimizing travel expenses/planning-supervision costs.
The big question is how to supply decent macro quality gear to each student without blowing the budget. But the key is getting them to explore this ‘new world’ as easily as possible. How big a group are we talking about and what’s the gear budget?