Leeds festival please help:D?

Okay, so this year, I'm going to Leeds festival with my sister. We are both quite short and skinny, and we wanna be at the front for Muse and My Chemical Romance as they are our favourite bands :D so does anyone have any tips to get to the front or near the front, cus we want some pictures and we want to actually SEE the bands. We don't particularly want to stand there and watch some bands like BMTH (all day) since we aren't into that music... Soo? Also, how long are head-liners on for? Thankss :D