from more spending rather than scaling education. You don't need a full professor grading papers and you don't need a teaching certificate either.
If parents see benefits from smaller classes they can use their education allowance for that. If one teacher can do a better job with 30 students than another can do with 10 they'll figure it out pretty quickly and the one who can only get ten students in their class will get paid less and leave for another job. This isn't rocket science.