Re: "The chainplate will buff out and probably be okay"
I posted a while back about my chainplate experience - I took the headstay fitting off to polish - it looked fine but wasn't OCD shiny, as I require.
After buffing it with a 1/2 horse buffing machine I noticed what looked like a faint hairline scratch across the front surface of the tang portion below the welded portion. You had to catch the light across it just right to even see it. I buffed it some more but it was still there. I held it at both ends and pulled and it slowly bent like taffy until it snapped across that "scratch".
I immediately pulled every chain in the boat and made up new ones which I had electropolished.
Crevice corrosion can be VERY subtle.
I, myself, personally intend to continue being outspoken and opinionated, intolerant of all fanatics, fools and ignoramuses, deeply suspicious of all those who have "found the answer" and on my bad days, downright rude.