I was curious on the front snaps that you drill in the window frame. Where do you drill them? On the flat drip rail or where the frame starts to slope upwards the instruction are not the best and I cant tell if its 3/8 of inch from the outer edge of the drip rail or 3/8 from the rear of the drip rail up the windsheild frame on the slope. I hope this makes sense. I would like to get it on today. Thanks Blazin 72 1972 K5 350 vortec, 4 inch lift, with nothing else important.