For Rig I prefer whole juvenile crabs with shell on and legs on so they can be wrapped up the shank or trace to stop the crab slipping down over the barb . If I get stuck with massive crabs ill take shell off and legs off one side then fold in half and bind em on . The big crabs are hard to present naturally but if you can get a juicy crab bait on without it falling apart then its going to work anyway.
I have been having just as much luck with whole raw Australian Banana Prawn and have had a day or two when mussel baits have been the saviour. I dumped the Vietnamese prawns I had the seem to be good for f*ckall .