I was able to find some heat treated (grade 8?) flat washers, that fit over the kingpin just about perfectly & had no “overhang” beyond the edge of the the top bush, at my local hardware store. They never bent/distorted & were around 80 cents apiece.
Anymore these days though, I’m running my trucks stock, out of the box, so to speak. I’m not even tightening them shits down, even though I prolly ought.
‘Course, I’m pretty much on Indy, Thunder, & Ace only, so I’ve got nothing to add as far as Ventures go.