It doesnt matter what color primer you spray. You need to spray a sealer after you you sand the primer and prep it. The sealer can make a dif on the color if you base coat is thin. You can spray sealer from white-black. So with your color I would do a light grey. Then 2 nice coats of base and a fog(misting it to get the metalik to lay down and not mottle or tigerstripe) coat then 2 coats of clear and you should be good.