Lets see....... isn't the A Gleaner, the Massey, and the Challenger the exact machine? Yes there was testing done on the Axial Agco built machines, maybe not in the silver color but in red or yellow clothes. I have 3 class 8's, and 4 class 7's and 1 class 6 running in small grains and they all do very well.
If you are trying to close the rotor to thrash the crop you will overload the seives, speed the rotor up. If you close the seives to clean the sample you will run grain out the back and get a dirty sample because you stop the air flow. Take most of the rotor knives out for dry crops. I leave a few in in a spiral auger type configuration to keep the crop moving to help keep the seives cleaner and it makes for better straw if you want to bale behind the combine. The 3 Class 8's cut for a farmer that dryland farms 80,000 acres so have 40,000 to cut each year, these three machines cut 1/4 of the acres and custome harvestors cut the rest with green red and silver machines but they own the Challenger machines because they do a good job in wheat, sunflowers, millet, and dryland corn.