We use the 'Gordon touch'. First concave is large wire with cover plates. 2cd concave is small wire, 3rd is large wire. Trying to save the straw we use two smooth pan grates , using a keystalk grate in the last position,and of course we have a set of 'Gordon bars' installed.We also run a Peterson sieve (not reccommended for high yeilding corn)that gives great sample. Works for us.