But...
As you've probably noticed, teh factory shackles have a mild bowl where the bushing seats. However, the aftermarket polyurethane shackle bushigns tend to be flat-faced (but I'm sure they mush as needed).

My original beef was the welding aspect. What about getting some 1/4" flat and bending the metal to the correct shape, then drilling for new bolts? would work well with poly bushings adn 9/16" dia bolts.

Teh cost is adding up, though.