Yep Billy, that's exactly why I use .035 only. With the welder settings right, and a cool hand, .035 can do as good as .030. That said, I don't have to weld tin roofing!
The last welding job I had was TIG welding Alum sheet. I had to make splice joints so there machines could continue to rull out the sheet. The material was .011 of an inch thick so the total thickness was .022. Hijack over.
.035 wire works good I keep .030 in my machine at home mainly cause I find myself doing like work at home and heavy work at the shop.