Hey guys. Looking for my first G1. I am looking at the used issue ones on eBay and was wondering about sizes. I have a '39 Aero A2 from Goodwear in size 42 and it fits well but is a bit snug in the armpits. I weas wondering with the biswing back if I should get the same size or if I should go up a size to get something with a bit more room. I don't like the big baggy look and living in Florida I don't need to wear thick sweaters or anything under it. Just thirsts and dress shirts. Thanks!