That it gets hot in there is your clue that there is not enough air movement for summer, for sure.
I've never used a tractor; I have a large shed type building. It has huge areas on all 4 sides that are open air, in our warm climate. It is breezy in there even in winter.
In the summer, air blowing directly on chickens is fine. Helps to keep them from overheating, a real threat. When they talk about "no draft," they are talking about a stream of cold air being funneled at them in a northern winter. Actually, what is a draft in the winter can be a welcome breeze in summer. Actually, 60 degrees is practically hot weather to them, once they are feathered.
Maybe someone else will come along and give you some ideas. I'm not much use for a tractor, obviously. But let me give you one link that shows setups for warm areas, and how open air they are., for you to glance through
https://www.backyardchickens.com/t/163417/please-show-me-your-hot-weather-coops/0_20