Clothing sizes are completely meaningless when it comes to determining body type. A size 12 in one brand is a size 8 in another and a size 14 in another one. Vanity sizing is of course worse for women's clothes, but even in men's clothing it's ridic:
Determining what 'guys want'....pretty much they need to see you naked and/or close fitting clothing and they'll know it when they see it. Numbers are meaningless.