If you guys look at post #6 close. you will see that is about the weakest link in the setup, and was not designed to fail. Nobody would design something to fail first. You build it to last. PT happened to chose a weak joint, and this has been further compounded by several weldings, maybe not so good . You don't even need a swivel joint for the rollover link. About the only place that you see that is on the 3pt, and then then you can tighten up on the side links to steady the load. You do not want something to break when you have that expensive machinery you are trying to move, or that load of wet clay, etc. especially working around people.
If you are going to use the same rollover link, at least add two 1/2 thick by 2 in wide steel about 6 in long. along side the shaft, with holes drilled out.
If you want strength, do this. Find some DOM tubing with an inside diameter of 3/4, with a wall thickness of 1/4. Cut it to the width of the inside legs, about 2 in. Find some steel the length you need, and 2 in wide, either 3/4 or 1 in thick, or two 1/2 steel pieces. Cut a 1 1/4 in hole in the steel at each end and weld in the DOM tubing, then drill for a grease fitting. Then you can be satisfied that something else will break before this rollover link.