Replying to edges for rails

This year i'm getting my first pair of twintip skis, and so i'm most definitely gonna be attempting rails. I've never really tried anything other than boxes, so i don't know much about it.

what i want to know is what about the edges of your skis? do you guys like file them down all rounded and stuff? if so, do you just do it under the boot? because even though i'm gonna be hittin rails, i still want to be able to blast mach speeds and be able to ski all-mountain without much problem. help me out.
-------

damned TWO PLANKERS