I had them mounted on my dock for a 22' Pursuit, in a canal that got moderate traffic with most boaters being considerate.
I mounted one for the stern cleat and the other for the bow cleat. Both of them were set up to attach to the cleats furthest from the dock & tightened down to put as much outward pressure from the whips. In the 5 years I used them, I never had a problem where the boat was banging on the dock. As a precaution I installed rubber bumper strips mounted on the pilings. Wind didn't seem to affect the positioning of the boat as much as large wake coming off large sportfish if they were going too fast.