Wouldn't it make more sense to put the wood arrow signs in a wood frame instead of metal? It shouldn't be too difficult to make them. Just use a grid size of 64, create the brush with that texture, and then you can rotate/flip if needed, lock (alt+l), and move it wherever you need it.
I would flip (use a -1 scale) the other horizontal arrow instead of rotating, so the shadow casts in the correct direction (unless you're putting a light under the arrow in the map).
