Fran from one that lives in a country that uses galvanised metal on a lot of things ranging from shed walls,roofs,doors,patios and water tanks. I can only suggest a couple of small things with your texture, firstly raise the bump up a tad(bout 5-10%) to give it that rough galvanised look and lower the reflection on it, you wont see much reflection on any galvanised metal. grab some and polish it and you'll see what i mean :) Just my doggy kibble worth

I have opinions of my own -- strong opinions -- but I don't always agree with them.