planning a small 12ftx15ft shed slab. Shed will be light more or less about 200lbs. Did a little bit of research and now my question here is do I really need crushed stone underneath? by the way, I got no issues regarding water at all. I have some 1"-1.5" stone leftover, can i use that, or does size matter at all? And is rebar or wire mesh necessary for this? Just trying to figure out the essentials for now.