73 E body front disc brakes conversion on A body. Where did I mess up?

Okaaay, gotcha! Sorry for the confusion- it just wasn't making any sense in my head!
I have never come across that on a ball joint before, Proforged, Moog, or whatever.
What I would do is use appropriately sized machine washers (not just normal bolt washers- use machine washers) in the recess between the ball joint and the spindle.
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Should be available at good hardware stores, Fastenal, McMaster-Carr, etc.
Glad we're on the same wavelength. I agree with you on the washers. Should not be an issue. Thanks for your persistence.