At your size the epic may not be the best choice. I have heard from a matually sized friend that it feels squirrily at his height. Besides that fitting is very personal and really there is no tried and true way. I am the exact measurement you are but prefer a really slack bike. I find it fits better and is far more versatile than a 'typical' xc bike which is more of a racer stance.
this should give you a basic idea of what and how to fit
http://www.coloradocyclist.com/bikefit/