I've never had to deal with rusting at that level. I would talk to the local paint stores to see how other local painters deal with it.

One of the things that bothers me is that if guys can't see rust, they thing it hasn't started. I've been told that it can start on a microscopic level, before it is visible.

As far as I know, all of the common cures involve phosphoric acid. It is in metal prep, and in self-etching primer. It changes rust from iron oxide, (which is an ongoing process) to iron phosphate (which just lays there)!

I can understand living with hurricanes, in Florida, but if the rust is that bad.........! :-)