Running a 17.5ft head in 80-100 bu wheat. Running around 3.7-4 and it is doing fine. Not loosing hardly any out the back, but I am getting some heads that are not threshed out in the grain tank. It is always the last 1 in. or so of the head, but there are not any unthreshed heads on the ground. Also I am getting a little bit of chaff in the tank and there is threshed kernels in the tailings. I have it set by the book. But maybe a little tighter on the concaves. It is a standard rotor and it has 3 of the cover plates installed on the concaves. We are running large wire concaves. 1st wheat harvest ever for me. Thanks.