This is an old trick I learned many years ago from one of my mentors. I take it for granted as being a pretty basic move in aligning panels but again today I was working with an experienced pro who had no idea what I was talking about when I said to “Shim the hood down”. He responded “Shim it DOWN, what are you talking about?” I have had MANY techs do the same thing when I say to "shim it down". Again, this is basic stuff but I guess because it is kind of abstract and you have to look at how the hinge works and then it is clear, but until then “Shim it DOWN?” is what you think.
You can see by photo #1 that this hood is up a little. Number 2 shows where you would put this shim, and #3 and 4 show how the hood is down quite a bit with this shim being installed.
This is of course the same way you can lower the trunk lid on most all cars made for decades. Those ones with the non adjusting pivot at the front like a 68 Camaro, just shim down that hinge at the bolt closest to the rear of the car and the lid will come down.