Hemi Hood Scoop

I have a bolt -on Hemi Hood Scoop and I'm getting the hood ready to cut a hole in the hood for Carb filter clearance and I'm wondering if there is a correct placement for the scoop. I'm sure it needs centering but is there a common distance from the rear of the hood? What does everyone do when they install the scoop and what size filter is most common to use? It's a 540 cu.in. with a 1050 Holley on a Indy Max Wedge intake. Thanks Ron