me and my friend are gonna build a box, but we need some advice. we were thinking to make it out of wood with pvc piping on the side, but we were also thinking of making the whole thing out of metal. and we live in the city, so what kind of box should we build? We were thinking just a straight or a down flat down. if you could give us advice as for its our first time doing it, thatd be swweeeet