[Tye Belcher]

A good way to do it is add a grid effect to a transparent video layer above your footage. Change the “Size from” option to “width and height sliders”. Then in width, make it a 3rd of whatever resolution you are shooting at, and same for height. For example, If I have a 1920 x 1080 composition, I would make my width a 3rd of 1920 (640) and my height a 3rd of 1080 (360). This will give you the right scale grid. From there, you center it on your comp and you are set. I would suggest making presets for your most common resolutions. Hope this helps!