Also... Ordered these!
They should fit really well. I made my notch too high initially and want to bring it down. Got them from Applied Racing Technologies. They are 2x3x.120 and a bit lighter duty than I want but I will tie them to my four link cross member with some 1.5x.120 tube. The rear of the frame only supports half the bed and the fuel tank. I think it will be fine. Plus each rail weighs significantly less than each of my damn over built notches.