You shouldn't have to choke an STS with those filler strips. Thats Deere's fix for inadequate threshing components. If you run an extra narrow wire front concave like the PF Parts you should never need those strips. Then you still have separating room without allowing whitecaps through. Also block the huge gap above the right concave support bar. This will stop whole heads from falling onto the precleaner. The last step would be to run better elements like the PF kit. Their 9 larger elements replace the 15 small ones. They use less power, run smoother, thrash better, and allow wider concave clearance which equals more capacity.