Just spitballing here, so hold the pitchforks please.
What if you split the classes further.
Group the 1st 17 in 6A LARGE
Next 16, 6A SMALL
5A LARGE the next 16
5A SMALL the next 17
Emphasis on grouping schools closer in enrollment 1st, then by geographic location.
And yes, I'd throw the 4 largest schools in the state into the same sectional and go from there.