Aaron you are giving me the willies, I have the exact same adapter on my larger Massey running my Woodmax
chipper. That adapter, a Speco I think, was super heavy duty, a serious chunk of steel, and I was impressed. Not so much now...and worse, I didn't see any set screw on mine.
Needless to say, I'm checking that out today.
Why didn't your shear pin break first? Sure am glad I'm not dealing with all that salt any more. Just tears up your machinery.
Unless you somehow could get that weld perfectly straight, I'd be worried about out of roundness damaging bearings. And I often have to take the pto shaft off on the implement, not the tractor, just to get the darned thing off. I hate pto shafts with a passion. Someone has to invent a better connector...