Replying to Need help with detuning

i searched and searched and could'nt find a thread that answered my specific questions.
i have a pair of k2 extremes and want to start hitting boxes and rails. i want to detune/file my edges down so they don't get caught and so they are less likely to crack or chip. but what i wasn't sure of is where to detune them. i figured right under the bindings but do i file the edges around the front and back tips to i don't catch an edge when i land switch or just not perfectly straight? or do i go down the whole length of the ski when i detune? thanks in advance