It all comes down to making use of what works for you. What I said was 'on average', or in other words, it's a generalization. There are some absolutely fine women who love them big ol swole dudes. In fact, the finest girl from my high school ended up marrying some ol Demarcus Ware looking dude. When it comes down to build or anything else, you have to use it as an expression of your own personality as opposed to 'what women want'. It's all about having that look that makes you feel confident about yourself and getting in where you fit in. Different women like different things, so instead of trying to figure out some 'optimal build' of what women like, go for that build that will make you look at yourself and say, "Man I'm fly."
If you absolutely must have a rule, I'd say you are reaching the upper limits of general attractiveness when you start hitting that Reggie Bush or Dez Bryant size. You go larger and you'll get more dudes than women complimenting you on your build, like 'yo man that dude is massive.'