DRUMS01
Here are some of the photos we were using for examples:
From personal observation, there are few things as varied in appearance as Wehrmacht gas mask cans and the German mess tins. Everything from a blackgreen to medium metalic gray (for either component).
So, you have some leeway in what you want to commit to.
The surviving examples are typically 80-something years old, so you get a range of appearances. None of which is helped by how the East Germans kept producing the mess tins--although I think those are a touch more blue-green than the Wehrmacht examples.
This project is moving right along, and it keeps looking outstanding.