This is mine I just made the other day from a vinyl rain gutter. Very light weight without the wood.But very complicated to move. My CX's are in a tractor that is moved daily. I hang the troughs on the wire sides.
Should be able to figure a way to attach it to the wire sides of a tractor. If metal is for sure stainless steel should do okay for FF but if it is galvanized aluminum like most older feeders it may not do as well. But if they are only fed in meals where they eat it all quickly then it probably won't matter. Do you have a pic of your metal troughs?