You can tilt the extensions (the little concave) out to the other hole position to make it less aggressive. I always pulled wires on them as well, but not sure if that mattered or not. One thing I did do because we grow Strongfield durum was build cover plates for the extensions. I just welded two bolts with the threads pointing out on them and built a plate of sheet metal to be held on by those bolts. I think it helped get a more complete thresh when I had covers on the main concaves. It made sure that butts and heads couldn't escape until they got another crack at threshing.