Yeah do some searching. I bought paint from those folks since all the colors are not locally available and some compatibility issues sometimes with the Duplicolor stuff.
What I’ll say is that all the rust needs to be cut out or ground off or neutralized or it comes back. There are acid type products that will eat the rust if it is light or there are coatings like Por15 (but the rust can continue under the coating). Regular body filler will absorb moisture so you can’t use it to fill holes. Not the same problem with fiberglass. There is a fiberglass putty that works pretty well with or without the mesh and won’t absorb water. Once you have a good base of the fiberglass, you can use body filler over that. So I’d do some serious cutting and grinding on the inner portion too. Use an acid conversion like Dupont’s, Por15 on it, fiberglass with the mesh over any holes, and finish with body filler. Prime at least any filler right away so that moisture is not absorbed. Those people you see running around town with unprimed body filler patches don’t know what they are doing and rust will be forming underneath.
Don’t remember his name anymore but one of the youtube guys was pretty good but swears constantly. Mostly major welding but he did use a NAPA spray on product for rust that he seemed to think was pretty good. He moved up to Utah and was starting a school. You can’t watch him with any kids or the wife around though. He is that bad.
Now that I think back, in the 60’s they were pushing using the aluminum tape and filling over it. Just rusted away and didn’t work. Fiberglass mesh is not perfect but if the rust behind can be controlled can be a reasonable repair.