160 amps is to high id be running between 50 and 80,u will blow holes in the panel.As I said slow down the speed off the wire and im pretty sure it will do down to 1mm sheet metal also its the opposite to stick welding where u drag it from left to right if your right handed where mig if right handed u go from right to left as the gases that are connected to the mig dispurse the other gases also to do efficient spot welds u start in the centre and do a circle spiral,if that makes sense.I have a cert 3 in welding but got that over ten yrs ago now and havent welded in a long time.