another thought. On the cat 0 side, either build one side of the lower hook up points removable OR build one side so that it swings like on a hinge. Not both sides swinging, one needs to be solid/ridgid, won't move. But one side swinging out will make it easy to hook up the cat 0 implement in a fast easy fashion. The lower tabs only need to be 3-5" long, keeping it as close to the adaptor as possible. Top connection at whatever length it takes to pull the implement level. Your adjustment is on your tractor toplink to adjust your whole adaptor/plow combination.
My neighbor didn't have that much trouble on his lower pins after adding some length to his chains but the top link gave him the most trouble. With this adaptor, both sides will fit properly and implement is sturdy, not shifting and him having no control of it wandering side to side.