You found my cameo appearance.....
Not only did I find it, I saved it in favorites files. I've spent countless hours watching welding videos on body panel sheet metal. Following the instructions on those videos yielded some results but, there was something very important missing.
You covered all the aspects and procedures to successfully "mig weld" body panels. Not one other video I watched every mentioned setting up the welder for open air welding. That was key for me, as well as grinding down the weld, then planishing. Repeat until welded up.
This winter I will resume practicing tig welding for the benefits it provides over mig welding.