Nathan, 600 rpms on the twin rotors are not that fast. I don't know your crop conditions but we run a TR 99 beside an R72 and the 72 will have 900 to a 1000 rotor rpms' and the TR because of the smaller rotors will be doing 1300 + to do the same job of threshing in wheat. Of course beans are a lot slower in rotor speeds but we have had no troubles with cracking beans with the TR.