There are two things necessary to prevent a toilet from leaking at the flange: a good flange, and a good seal between the flange and the toilet. As I'm not a plumber, I'm looking for how best to ensure no leaks in my repair.
Here's the current state of the 60 year old cast iron flange. It was so old and the wax ring had dried out and I had to use an old wood chisel to get down to the flange. I wire brushed with a drill and threw some enamel to prevent future corrosion.
Unfortunately, the notch on the right had been leaking and corroded the flange for the bolt into a V-shape. For a few bucks, I bought a steel plate and used some epoxy to attach it to the under side of the flange driving it upwards with some shims. I'm just going to use my stick welder to fill in and grind down, and touch up the enamel so the flange lasts another 60 years. Should I augment the flange in some other way, and if not, is a newer waxless solution maybe necessary since the flange isn't in the best condition?