Hexavalent chrome is the way to go, but try and find a plater that uses it and it will be more expensive because it is a carcinogen. It is EPA regulated as is everything related to plating. Most platers will use trivalent chrome because it's safer, not as bluish in color as hexavalent chrome but probably what you're going to get. And also the copper strikes are important for filling the scratches and divots, but most of the protection and shine comes from a double nickel strike. The copper first, then semi bright nickel, then bright nickel, then the chrome. Find a plater that takes pride in his product, he will be pricey, but don't forget that there is a lot of labor involved in quality work.