Tube frame would be great if I was replacing it all. Probably more rigid than the hat channels too.
I made good progress on the drivers side this week. I had the channel made up and got it fitted & welded in. I think it came out pretty well. I primed , then coated the channel with eastwood internal frame coat before welding in. Should not rust out again! Pictures don't show it, but I punched holes in the channel flanges and spot welded in from there after welding in the new sheet metal. I still need to install a new panel above the engine bay brace bar, then on to the passenger side.