Bass have seen bait on the bottom, bass have seen bait suspended up above them, sinking down or swimming past them, but never exactly where a dropshot suspends the bait. Especially on 6 lb. test, fish have never seen that presentation. Color is often secondary to me. In fact, some days I get a weird feeling as you could dropshot any bait in any color. The key is just the straight suspend.
Any bait can do that on a dropshot.
Hula grubs work really good. I don't think craws act like that. The dropshot is something the bass have never seen, so they hit it. I don't think they care what the bait is or what color as much as putting the bait somewhere it has never been before. This line is pretty tough for 6 lb. test, but I still change it daily because it twists up badly due to the dropshot.