We did that in our R65. It worked very well. Moves material thru the cage faster and keeps material looser to allow the grain to come out.
Its backwards from what you would think. It took me a little while to wrap my brain around the idea. The best way I can explain it is since the material is moving from one end of the cage to the other faster, there is less material per square foot thus letting the grain out easier. The slower helicals causes more material per square foot across the cage.Boy I would think rotor loss would be a concern. I talked to one guy that did it and he fought rotor loss. He did say it was great in green stemmed beans for through put.