moisture, variety & weather conditions these determine how the machine will perform we run a 2188 with AFX in conventional rice as trennase, cocodrie or chenier, rotor 700-730, fan-1120, top screen 5/8, bottom 5/16+, vanes in the middle position except for the last two are in fast position, concave we open till we see rice left on straw then come back down till it's right all machines are different, hybrids as rice tek we can slow rotor as much as 650 everything else pretty much the same, now some thing that make a difference we had trouble with small straw when we removed wires out of concave so we run the first one with all wires an the middle an last with every other one removed made a big difference also I noticed as we get to the center of the field or in a point we get more small straw so I got on the combine an found as dad would cut after the first round he would overlap about 2ft in some places an cutting a couple of inches of the already cut straw, I can tell where he is in a field by the sample, he's 77 an he loves it! good luck PS we also run a 25ft draper