I also like the thought process here. But I think 4 didtricts is the magic number but back fill empty spots with 5th and 6th place finishers.
Use the state pairings to set as a priority for the back fill.
If its 1 vs 4 and 2 vs 3 and there's an open spot in D2 the D3 gets 1st option to fill it with its 5th place person.
If there's 2 spots the you go thru all the 5th place people and the thru the 6th place people.
I like the ideas here!