How to fix sheet metal holes?

My Dart GTS probably has a rear clip from a GT; it has holes in both rear panels for trim strips and a GT badge. They were all filled with body filler when I bought the car. I cleaned them all out and used a sheet metal patching method as described above. These photos are of the repair of a rust hole where the vinyl top met the body, but the process is the same.
Warping can be a problem, but as with any sheet metal welding, short beads with time allowed for cooling in between in the key. After grinding smooth (again using only short blasts), I use just a thin wipe of body filler.
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