The 11 hole AC mounted grain drill was made for the WD-45. It was driven by a gear and chain system which mounts on the left rear wheel and hooks to a gear on the left side of the drill.
They worked great on level ground, but when you went through a dip, the seed tubes sometimes got plugged up with dirt.
I have the 9 hole drill for my CA tractor. My dad planted a lot of oats and wheat with that rig. The CA is a bit light on the front when the hoppers were full of seed and fertilizer.