One other point, obviously there is nothing wrong with short sleeves over long sleeves, and the whole discussion is pretty silly. Even the issue of tightness is not so clear to me. Could somebody knowledgeable here provide a primary source that tightness is a factor in tznius? I mean a gemara or chazal, or even a secondary source, such as a rishon, or even up till the shulchan oruch or the nosei keilim.
I believe that in older times, heavier was considered more attractive than skinny, and for them tightness would even have been a negative factor in one’s appearance, and not a cause for attention. (Don’t all the older statues and paintings depict heavy-set women? Any art experts out there?) But at any rate, please provide a source for tightness.