Running a 893 with the Pixall rolls.  What I found is it takes a good feeder house speed to to really chop well.  Found 660-680 is the minimum.  640 if I want to leave it ragged.  After running red cornheads I find the green one limits my ground speed if I want to destroy stalks.  5.2mph if I want them chewed to the ground.  Often I can run 6 and it will leave a stalk in "some" hybrids.  Pic shows two cornheads side by side.  Green one closest and red one distant.  Red one is nearly 35 years old.  I might look into the clark rolls that have the CIH style knives?  Don't know for sure since I have never seen them.