What's the best base coat for ginger coat and leather coat?

Black primer is more suitable, and a brighter color like ginger is usually suitable for dark primer, which can play a comprehensive role.

Ginger is bold and needs a little restrained color to decorate it a little.

There is usually a principle to follow in dressing collocation, that is, bright colors and dark colors should be matched, so that you will not have any misunderstanding in dressing collocation.