I am running 1st gear, which puts me @ 2.5 MPH, in direct drive. I am taking 4 rows of 36" tall beans. I have the 21" reel drive pulley, and the slow speed auger drive pulley installed. Running cylinder adjust levers about 4 notches down from all the way closed (top). I put a brand new cylinder drive belt on this year; I always forget the difference new rubber makes. Spinning cylinder @ 673 RPM. Very little,if any, cracking of beans. Moisture @ 12.1%
Chaffer set to just lets unthreshed pods thru, shoe sieve set close to barely let clean beans thru.
I also run a SkourKleen, with the slotted soybean screen; removes ALOT of weed and pod halves.
I run the head right on the ground, and keep a sharp eye for rocks.
Best of luck!