I had to settle for a 70 series wire feed unit and a tweco #150 gun.I hooked it up on my new xmt350cc/cv.Bought 1.2mm 4043 aluminium mig wire and 1.5mm contact tip.I start my aluminium mig expedition .I had problem with drive roll tensioning and wire speed /voltage settings.Without the Teflon liner I have been able to mug weld +6mm thick aluminium pieces .My big problem is to weld 2mm thick aluminium sheets,the one used on the freight liner truck fuel tanks.Can anybody help with settings ?Could the optima be the answer to this issue?