Hey questions: I'm making a shield, and I was wondering: What kind of foam is best(like is that camp pad from Walmart good enough for shields or do you need something else?), and whats the best kind of wood to use(like oak, birch, pine, whatever, also wheres the best place to get the wood(home depot? ace hardware?)), also how many layers of foam is good? I was thinking 2 or 3. Thanks in advance.