I used two pieces on the outsides of the pre-existing mounts. I started by using hack saw blades as the size shape to make the arms. I used .040 for my mounts. That worked well but there was a little lateral movement. I made the mounts again, but made them slightly taller with a small 90 bend in the bottom. They fit right into the elbow of the existing bell crank mount.
So basically this exact picture, with the arms sporting a 90 bend extending out 1/8 inch.