Sean I had the very same problems with my blasting setup, so it's the old fashion way for me, sanding and grinding, but some stuff just doesn't come off. That's where the por 15 really is nice. It bonds like glue to rust. It doesn't like any greasy residue though. On my body panels I'm using one step rust converter, from Marhyde. It sprays on with a can and converts any residual rust to "black primer" which I think is zinc oxide. Works pretty good on my old truck. But a slow and tedious process for sure. Post some pictures as you go.

Also glad to hear you were able to find the POR primer. I bought my Metal 2 Metal online too, because I couldn't find it here over the weekend. A week later, I was at the local autopaint store(closed weekends), and noticed they sell Metal 2 metal and a lot of evercoat products, that none of the auto parts stores carry. So it takes a little longer, when I can't get in during the week to get what I want, but the guys there have been very helpfull!