cooking grates

Hi all from Australia just a note to Aussie UDS/smoker makers in Melbourne if you cant find Weber grates here ($56.00) for cheap ive found a guy selling Stainless Steel mesh On Gum tree and Ebay.I got 1 metre by 10 metres 25mm square weld mesh for $80.00.All ill do now is roll some metal rings...

I was wondering if it makes a difference when smoking overnight to use porcelain coated stainless steel grates or my cast iron grates in a Bayou Classic Ceramic (BGE imitator). In the past I've only used my cast iron for steaks and grilling. Any thoughts?