The first thing I did this afternoon was cut-out some steel patches for the rusted holes in the rear fender wheel-well lips. I roughly measured the size of the three patches I’d need and cut them out of 18-gauge steel using a metal cut-off wheel in my angle grinder. I shaped each as a rectangle, and rounded the corners because welding sharp corners can be a challenge. I find it easier to weld the radius of a rounded corner.
Here is a picture of the rusted hole in the right rear fender lip that I intended to patch, and one showing that my patch was large enough to do the job.
I traced out the perimeter of the patch on the fender using a black marker.
Later I will cut-out the bad sheetmetal and weld in the patches.