Hi mate - the way I approached them was to lay the silver down first. Then lightly transfer the shapes on using your transfer paper. Here, you will need to look at many reference photos and using an airbrush, mist with a grey to the best your eyes can see, as close to the reference pics as possible. It may look a bit of a mess at this point, but it should

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From here, you will then re-stencil your shapes, making sure you are very exact this time. This will set the shapes up to be liquid masked (I like Humbrol Maskol for this). Once masked, the green layer is added, and once dried, the mask can be peeled, revealing your shapes with the misting. Then all the weathering and topical detail fun starts! I think I have pics of the process in my ROTJ thread if you need to get a visual. Best of luck bud!