To add to what the other guys said. Opaque colors are what you use when you want to cover something real well. Transparents work well when you are blending colors or doing scales.
Guess it really depends on the colors of the plug and how you want the scales to look. I really don't do them much anymore. Last ones I did had black as the base with olive over top, or pearl gold base with olive green over top. See no reason that you could not use transparant over transparant if the colors worked together.
Hybrid Mode
