You can use a large wire with all wires installed in the 1st position and a round bar in the second and third position.
This will work in both corn and beans.
I had to take wires out of the second and third concave in beans with both my 1460 and 1660 or I had rotor loss. Using the large wire in the first position will give you good initial separation and the round bars will stop rotor loss. In corn large wire in the 1st position won't hurt you and the round bars in 2nd and third will really get the corn out. The first vane in the cage can also be put in a slow position for beans to hold the crop over the first concave longer and this also won't hurt you in corn.