I am not familar with a specialty rotor but I would think you could get to 5mph pretty easy. Are you returning much with the way you are set nowIJ I have found with my 2388 and standard rotor the slower I can run the rotor and still get it out of the head the better for rotor loss. Unless it is really dry you might have to close your concaves if you slow the rotor. This has helped with rotor loss for me, You have to be careful or power will become a issue. like I said I have never been around a specialty rotor of spring wheat. Hope you get it solved, I have cut 70bu wheat at 5 to 5.5 and not had rotor loss, shoe loss is another story. Good luck