@Dadais was really helpful in creating a grid over a map for me which makes it mostly "diamond art" if you've ever done that before, so I should be good here.
If either of you wanted to be extremely helpful to the community sometime, an idiot-proof, step by step instruction thread on how to appropriately determine the dimensions of the grid, and create and layer the grid in a paint program would be outstandingly useful. Perhaps the next time one of you makes a map, you'd be willing to document the process?
I know I certainly have other scenarios (Germanicus and Caesar come to mind) where I would like to remake them with better maps than my old efforts! I'd love to get a better handle on how to appropriately size a grid to a picture and overlay it as a layer.