Any Tig with high frequency. Old millers or Lincolns with hi freq are great if you have the space. I like er70-s2 1/16” rod. Some people like silicone bronze rod because of the low heat required. In the old days when I brazed often I had trouble with Bondo sticking to brass so I’ve stayed away from bronze tig rod. #4 cup and 1/16” tungsten. Easy to see around a #4 cup. I move around the panel I’m welding after tacking the panel. 1/2” to 3/4” long welds. I keep an air gun close by and cool off the panel after each weld.