Your window rust looks just like mine. The real problem is found when you check in the glass channel. Mine is rotted badly while most of the car is pretty good.
The glass channels don't have any drainage. They become catch alls for decaying leaves and other organic matter. This stuff gets under the chrome trim and holds water against the metal. The trim retainer pins usually have scratches on them and rust gets a tooth there to crawl under the paint. These window channels would rot enough to leak in four or five years when cars were kept outside. My '68 was leaking in 1973 when I repainted it.
Folks used to put RTV in the glass channels to fix leaks started by rusting. RTV was pretty new in 1972. It did a lot of sealing jobs well but this wasn't one of them. I used it myself on my bird back then. It contains acetic acid which accelerates rusting. Rust gets under the silicon which holds the water under it where it can't get out. Rust continues until it rots through to the inside of the car. Meanwhile the rust crawls underneath the paint, just like it has in this photo. When it crawls past the chrome trim that is when you first notice it.
Rust bubbles next to the Chrome window trim are the tip of the rust iceburg submerged below.
A lasting repair is difficult and expensive. Clean off rust and cut out rot. Weld in metal patches where rot is be removed. The windows need to be removed in order to repair the rust and rot. Anything less thorough is inviting brand new paint to fail.
Rust expands as it forms. That is why it cracks the paint. Cracked paint permits water intrusion. That's why it is pointless to paint over rust. Forget the weasel stuff. It can't work unless the rust is gone. If the rust is removed there are superior products. You'll never see an auot body shop using paint over rust or rust encapsulator products. That is because they pay for redo when it fails.
