We harvested a lot of soft white wheat acers in Idaho over the years as a custom harvester. We ran Specialty Rotors exclusivly. Without knowing exactly how your machine is set up, I'd just be guessing as what to do. First, I'd say that 3-3.5MPH is about all your going to do with that much yield and putting that much straw through the machine. One thing we did was never to run all three small wires in our Axial Flows except in some hard to thrash varieties of hard red wheat. Try replacing the last concave with a large wire one. This helps start pushing the treashed grain through. After all, most of the treashing is done over the front concave. After that, we need to start thinking about seperation. In some varieties, I've even put two large wire concaves in the rear leaving only the front as a small wire. Then, use your concave setting and rotor speed to adjust your threshing. I'd say around n1 is a good place to start for opening and 900 for Rotor speed. I think this will get the crop threashed right in the front. Then the large wire concaves will start seperation earlier, not waiting untill the crop is to the grates before seperating. You'll gain some ground speed this way. Keep in mind, a combine can only handle so much material period. We ran 25' head on our 1688's, 3.5-3.8 mph is about all you can expect to do in 100 bu+ yield and heavy straw. Air foil chaffers are the only way to go in small grains, sunflowers, dry beans, dry popcorn and dry corn. The only time we need a regular or deep tooth chaffer was in high moister corn. Good luck, CM