I apologize Damon, the pic above is a standard bracket for the rubber stop on a motor boat trailer, ignore it. So you want 2 lengths of channel steel approx 8" long, and you want 2"x1" channel steel, 2" base with 1" sides. Invert the channel steel so that the open end is up,
drop the rubber stop into channel, drill a hole all the way through sides of channel for a bolt with lock-nut or a pin to "mount" or secure stop in place. If I remember correctly, the base of the rubber stopper is 1" in height so when you drop it into the channel, the steel lip sits at the base of the "V". Space the 2 rubber stops on either end of the 8" length of channel steel so you have a gap in between for drilling holes to mount your bracket at right angles to the cross-arms.
Hope that helps.....
R