Graphic design grids look easy until you try to hang actual frames.
I was inspired by those sleek magazine spreads with perfect alignment. So I mapped out a grid on my bedroom wall for some family photos. But the frames are all different weights and the hooks never line up right. Now my 'designer' wall just looks like a haphazard gallery.
A trick I learned is to make paper templates first. Trace each frame on newspaper, tape those up and adjust until the grid looks right, then mark where the hooks go.
15 family photos needed a grid layout in my hallway. I used a chalk line to mark straight guides every 12 inches. This method saved me from multiple bad holes.