I like to use transparents and candies because it is more versatile and easier to work with. With an opaque, you lay the color then your done. WIth a transparent or candy, you can lay it out, then use multiple backing to achieve different effects. Lay a transparent or candy blue, back it with a pearl silver, you get pearl blue. Back it with a coarse silver, get metallic blue. Back it with a chrome, get anodized blue. Mix with pearl, metalic, then black, you get an irridescent blue. If you wanted to get a deeper pear, use gold. There are just too many combos, but you get the picture.