Front arms, one still to be welded.
The rings are 3", machined for proper interference fit (though it will probably shrink more from welding).
I used a 3" hole saw to cut out the mount, with the saw just skimming the inside of the original balljoint bore. The rings are roughly 3/8" thick, and the new ball joint is roughly 1/8" larger in radius, which move the joint roughly 1/2" outboard.
The forward leg of the arm is just sliced, bent, and re-welded. It's as much as I dare cut.