So all I've used are the 4.5 standard size. Nobody around here sells robos so how fat are we talking?

 Not that fat you think of, Just little meaty compare to regular ones. They are my favorite on 6" for dropshotting.

nose hook with #2 or #4 Mosquito hook and you are good to go.

The fat is a little bigger in diameter but not as big as most finesse worms, but is more buoyant.

Higher price is the 4” FX Sculpin worm, my favorite for nose hooking.

Tom

About the same as a trick worm.mybe a hair thinner.