The back of a peeler crab will be soft if it has already shed it shell, if not you will notice that it will be lifting off.
The way I put them on the hook, is to take the legs off ( I keep these for tipping aswell ) The legs will just pull of easily, the shell should either be off or if it has one it will pull of easily aswell.
A lot of people cut out the lungs which are on both sides of the crab just hiding in a small pocket above the legs, its up to you if you remove them though.
I cut them in half and whip a lot of baiting elastic around it before threading it on to the hook in a similar way to putting a worm on.
If using whole crab again remove the shell and whip it up with a lot of elastic and thread the hook though.
Big hooks are a must though as crabs are quite a large bait and could easily mast the hook point.
As for the species you can catch, I think the most obvious one would be cod in the winter, they go crazy for peeler crab but bass also love them. Flatties will go for it aswell and thats what I use the legs for, you can also catch thornies on them, smooth hounds, doggies and conger..
Ive never fished west bex but I would try a pulley rig with possibly a 3/0 or 4/0 hook anything which has a good size gap between the hook point and shank of the hook to allow for clearance of the crab and to allow the hook point to protrude , Might be a good idea to use the pennel style of hook set up aswell if you using big baits.
Obviously thats my thoughts but if anyone else wants to add something I would be grateful
Crabs have to shed their shells periodically because they do not grow to keep up with the crab's growth. They skulk about hiding in ravines and under rocks when they are in this vulnerable state and when they have actually lost the old shell are completely soft like jelly. In this state they are powerless (great for those who are frightened of crabs particularly the younger anglers) Peelers are often found associated with a large male who hold the female underneath. Thus the 'underneath' crab is always a peeler, so put it straight into your carrier witha few bits of weed. Otherwise if a crab looks 'well-worn' have a close look! You might see that the shell is cracked at the side of its body as it gets ready to lose it. Traditionally anglers will 'test' the last segment of the leg. Pull it off carefully. If it's a peeler it will pull off to reveal a soft and fresh coloured segent. Remember to put back any rocks you turn over exactly as they are in order to protect the micro-environment that nutured the crab - well you are going to return are'nt you?
Hooking is fairly easy if you're using bait elastic but I never bother removing anything that the fish can eat (and you lose less of the 'juice' These preparations are often done to prevent the deterioration of frozen bait or because the bait is being made more streamlined for distance casting. Think about how UNaerodynamic a crab is with legs flying. However this is not an issue if you are casting short, deliberately. If you're a beginner watch what those who are catching prepare their bait and copy them! Cut big ones and bind on. I've started using circle hooks tied on so that the point is easily accessible to the fish. If you bury the hook then let the fish run with it before you strike - it's advised it seems with circles anyway! Good luck!
I live in Poole and fish Chesil alot. Lots of different species will take a fresh peeler, so you need to balance your tackle to the species (if possible). I have caught Plaice and Dabs on peeler and you will struggle to get them on a 4/0. I have used a quater of a crab or used the legs for tipping to catch Plaice on a size 2. I would echo the use of circle hooks especially in the smaller sizes for this type of fishing.
Obviously if you are targeting the bigger species (bass, smuts etc) you will need to step up the gear.
Circle hooks were designed for long lineing and so the fish is expected to hook itself and a strike might achieve the opposite effect (so I've read) . A question of my own-What's wrong with using normal ie. not peeling crabs? surely the fish can't tell the difference