I have used this and really like it but it's only been a few years.
Pricey but a can seems to go a long way. The included application wand is awesome. Stinks to high heaven which tells me it's good stuff. Got the green so I can see where it's been applied. Like I said only a few years but holding up well in the norhern Ohio rust belt. I use POR15 in accessable areas.
Nothing is going to stick well to a wire wheeled frame. Especially not POR. You’ll need a rough surface profile for good adhesion. Have you considered galvanizing it? There are special rules that apply painting a galvanized surface, however.
One idea that saw from another MUD member is to use a rectangular chimney sweep brush to clean the inside of the frame. The bristles are quite stout and the brush may need to be trimmed to be closer to the internal frame size. Once trimmed, it can be pulled back and forth through the frame to clean the surface. Labor intensive, but it can be a decent prep for things like the Eastwood internal coating.
Ive been working on my fj40 frame. I put several pieces of wire into my drill to clean off the inside of the frame as best I could. Then used the Eastwood internal coating. Took a short video. I think it worked ok, better than doing nothing.