I know it's awfully tempting to obsess on something that is easy to measure, like file size. I also know it's tempting to imply things like "twice the file size means twice the page load time". But it's not true. It's NOT true.
Productively optimizing a web page is no different than optimizing any other code. If you want to know why a web site is slow, profile it or run it through a tool like webpagetest.org. Don't just set off to rewrite all your loops to run backwards, or eliminate function calls, or reduce the amount of this or that without any understanding of the result.
Look at this video at 6m30s: http://channel9.msdn.com/Events/Build/2012/3-132
Productively optimizing a web page is no different than optimizing any other code. If you want to know why a web site is slow, profile it or run it through a tool like webpagetest.org. Don't just set off to rewrite all your loops to run backwards, or eliminate function calls, or reduce the amount of this or that without any understanding of the result.