Guys, Over the past 4/5 years I have used 1" galvanised steel rails to set my grade for installing my bedding sand. I've noticed that some of the rails are no longer true, as I remember them when I bought them. Some now have slight bends to them so I am weeding them out. Before I buy more, I had a question... I saw another guy using 3/4" or 1" cube stock, steel rails and wondered if maybe they were a more durable than what I have been using. Thoughts? What do you use?