As a rule I don't buy my clothings online. When it comes to manufacturing clothings for bigger folk the manufacturers can be all over the map. I, being a big fat fattie, usually wear a 3x shirt, but I've tried on and comfortably fit into a 2x to a 4x shirt. Slacks are even more insane, so buying online isn't really an option for me. I have to be there and ignore the size tab in favor to how it feels. Fat people hoe a difficult road--but I guess if it's so hard we should probably shut the hell up. As my friend Rich Powers used to say about soda--forget about diet drinks, if you're fat you should drink water.
I ordered today from a company called Jinx and they have some stunning designers working on stuff--plus they carry large sizes and have a liberal return policy. Sounds like a match made in heaven to me. I'll let you know what the finished products feel like. They clain that most of their stuff is pre-shrinked and 100% cotton..