Actually the idea of the copper in this topic is much much better than the Bison Salmon one. Though the execution was not yet perfect. The problem is that every RGB color turns out much too light in the game, which ends you up with a sh*tty brown color in ingame fdaytime, hence why the OP never posted pictures of that. The other problem is that the lighter the color is, the less shiny it will end up, hence why black steel is the shiniest. Therefore as a base color, choose black steel, and not gold. The gold sounds like it wil make it look more like copper, but the metal paint is only for the shine and not for the color.
I've been experimenting with the color, and RGB 35, 18, 11 with black steel and silver pearlescent made me end up with an almost too shiny perfect copper. Really amazing looking. I could go for pure white for extra shine, but it would end up too shiny... Wish I could log into XBL and make pics but I can't.