OK so im looking at putting a set of towing mirrors off a 1999 f350 superduty(the ones that dont extend) i have taken out my vent window im just looking for an oppinion from a welder or metal fabricator. I dont know what thinkness of metal to go for the replacement of the window to bolt the mirror to. I was thinking some where in the range of 1/8 inch to 1/4inch because i want it to fit in nicely but i really dont want over kill, but if need be i will. and i dont want to be doing 100mph(sometimes you just have to) and watch the damn things fly off.