You could use some ox-acetylene rod in a 16th to 1/8th diameter.. The raw length of rods are 36 inches long. Take lineman's pliers and bend an 1/8th - 1/4 inch long L-shape at the end for a spot tack. Weld it on and cut it off to your usable puller length with the pliers.
Or yeah I have covered holes up to 1/2'' by "bridging them with wire" set my wire tension lite, voltage low and increase the speed enough so I'm kind of welding lightly, takes practice.
But I like to "cheat my heat" welding with a thicker piece of metal to thin; like the thicker (o-a) rod to your .020 weld wire to the sheetmetal body. You have a way to stretch your arc into the base metal but no burn through it... Whatever shape of surface you want to restore or fix right; grab an old door or fender that best represents what your working on and practice your ideas and skills, filler material, paints or aftermarket tools.
Then you will figure it out.