leaf spring support for 74

[AmadeusCharger500]

I have a 74 satellite. I am in the process of patching rusty panels. I have found that the supports for the rearmost hangers are in danger of breaking loose.
This section is almost like a 6 to 8 inch frame rail parallel to the main frame of the body.
The metall is quite rusted from the rear bumper area and settling in to where the hanger bolts to the rail.
Can this be fixed by adding metal supports over the existing, or does it all have to be removed.
Also what guage metal should be used?

Thanks,
HH