I usually set them by feel, but probably 5_8th inch on the chaffer and 1_2 inch on the shoe. I set the front section of the chaffer closer and the back section more open. I run the fan as fast as possible without blowing grain out, usually about 1120 or so. Rotor at 600 and concaves at 4. Vanes middle position. These settings are estimates, I change them depending on the conditions. Here are my objectives in order of importance: 1)as little grain loss as possible even at high ground speeds 2)Run as little threshed grain through the tailings as possible 3)Keep the sample under 1% FM with few splits. Notice that the perfect sample is not that high on my list. As long as I'm not getting docked, I don't worry too much about it.