as far as the welds go they look good, looks like penetration is fine as there is bluing evident around the weld. Only thing I would mention is that working with sheetmetal you really should just be placing a series of spot welds, not a constant bead like you have in the pic above. If you simply use tack welds and work back and forth moving from side to side until the length is all welded. The tack welds will help keep the heat down and keep the metal from distorting.
Noah
Noah

