Correct me if I'm wrong - but doesn't the silver-impregnated stuff have to be in direct contact with the skin to get maximum scent elimination? That is - it kills the scent-producing microbes that live on the skin.
So wouldn't it stand to reason that it would work best if it was worn as the first layer, so as to ensure as much skin contact as possible?
When I was saying "over" carbon I meant choosing it over the other, I should have been more clear.