Hi ,I am about to do some welding on my Mk7 Transit. However before I get the grinder out to see how bad things are can some one please explain to me what gauge metal I should go and buy. I need to do some work on the sills and rear wheel arches although due to small amounts of rust I dont want to buy complete repair panels. I still work in feet and inches lol but I think you buy metal in gauges and this is where I'm stuck.