I did my aerator parts with spray cans before I attached them to my bucket. I weathered them so it was a mix of bright silver, graphite, and flat black (dust coats and dry brush). Don't over think it. The CRL is isn't rigid on how you paint it, so look at your favorite images and do what makes sense to you. I'm working on my 2nd helmet now and may decide to change things up. For the breather tubes, I used plastidip to give them a rubberized look. Looks better than matte black in my opinion. Hope this helps.
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