Sorry I can't tell if you are legitimately trying to help or providing a link to an article I read when it first came out just to make a point that css and media queries are the way to go.
If I need to provide a back story as to why I want a user agent solution: I work at an agency, I do front end design and coding.. with some js/php knowledge. I have a very old client site that my boss does not want to spend money on to fix, nor do we have the time, nor do the devs have the time to quickly test with me.
I came here trying to find a very quick solution. I am completely aware of the advantages and disadvantages and will definitely come back to this project and do it right through a whole css re-write.
But anyway thanks for your input.