My bil is an industrial engineer and spent 30 years doing wood truss design and work. Now he checks designs for compliance, etc. He does federal buildings, hospitals and schools besides std designs. He only does calif now. To make this short, he recommends wood trusses as being the cheapest way to go. He also said to find a co close by and have them design and make the trusses. Metal will cost much more and require a licensed welder. He won't be able to help you and could not give more advice without more info. But that's the jist of it.