Have you checked out the hi-tek thread on castboolits?
From what I remember they had a hard time testing hardness with the coating on. The issue with filing off the coating is that lead work softens (opposite of say copper or steel) so as you file you’re actually dropping the hardness.
I didn’t read too deep into it but it seemed like the only way to see what would work was the proof being in the pudding.
I have, but not recently. Several years ago maybe when someone was trying to push 3000 (maybe it was 2500) f.p.s. through a rifle with a powder coated load, and I think he had some success with it. I don't remember the caliber exactly, it was one of those metric ones like 6.5 grendel or 6.8 spc. It was right about when powder coating was taking off, and before federal offered it as an option in syntec ammo.
I'll take a look tonite at the hi-tek stuff.
I noticed the vid didn't give a measurement for how much lead was filed off.
If straight wheel weights will work with hi-tek up to say 1500 fps, then good enough.
It got me curious because either missouri bullets or bayou lists a b.h.n. of 16 or 18, so I got to wondering if thats before or after baking them.