I have two bins with sukup double screw stirrators in them. One is a 7,500 bu bin and the other is a 10,000 bu. The larger bin has the air tubes and I can't see a bit of difference in them. They both do a good job.
I have several bins. They range in size from 5000 to 20000 bu. Size doesn't seem to matter. The bins without tubes will sometimes, but not always, have spoilage on the north side of the walls. I'm guessing the determining factor is the outside temperature when I finish drying the corn with heat. Bins with tubes don't have spoilage. Your location might make a difference. I live in nc Iowa.