Apart from everything you said being true, my father is a high school headmaster and he says classes of 35 perform the best. Lower students are pulled ahead and

Apart from everything you said being true, my father is a high school headmaster and he says classes of 35 perform the best. Lower students are pulled ahead and they understand that they have to become independant if they don't want to be rejected. Of course, as you mention, the lowest 5% will have bigger problems than in smaller groups.