my 1st play with softies was with these crabs, I used a 7/0 gammy and threaded it side ways so the crab looked like it was having a wander, did not use any sinkers as i was only in 4m of water, had the set up on my saltfly, dam if it was not alot of fun, a slow bottom and even mid water retrieve did the damage, and on the fly they cast well.
I rig mine with a 4/0 circle hook through the middle then above that a ball sinker which is allowed to run up/down the line. I cast it out behind the drifting boat and allow it to be dragged along while actively fishing a SP in-front of the boat. I used it mainly on mad flats in shallow water.
Was quite successful mid summer when the Snapper were around down here. The only crab I had luck with was the gulp, tried a couple of other brands and only got nibbles.