I made a made a mounting plate out of a 2″ x 1/8th” strip of aluminum and drilled holes in it for the lower jackplate bolts. Take off the lower jackplate nuts, put the aluminum strip on and reinstall the jackplate nuts. This way I could use bolts and nylock nuts (with loctite) to mount the bracket in the center(left/right) of the boat. Im not sure if this is the best place, but it seems to work well.