Pull the legs and claws off, look under the right and left hand sides under the soft shell and cut out the brown (Dead mans Fingers). Form the body into a sort of sausage and bind it with bait elastic. You should have a sort of sausage shape oozing with juice. Feed the hook through the sausage and exit before you get right through so that the hook is well clear and not masked. If the bait feels loose on the hook use more elastic.
It depends a lot on whether or not you want an areodynamic bait because you're going for distance. Is it possible that Match anglers have developed a smaller bait to allow fish to swallow bait quickly? I'd be inclined to try it as already explained but consider other options.
If you're fishing close or in a rocky, deepwater mark just peel the back and sides. When fish eat crabs they don't seem to do any filleting! How often have I found masses of hardbacked crabs, legs, pincers and all, in the stomach of a Bass or cod. It may well be that the less you pull your peelers about then the less of the attracting juice you spill onto your boots before you cast! Use bait elastic but try to leave the hook point exposed. (Before we had the wonder elastic we used about 3" of Red wool tied around the hook shank first and then tied around the crab!)
Experiment a little! I'm trying these circle hooks at the moment and, having done my preliminary 'peeling', (I do none if it's a softy) I tie the crab on with the hook free, a bit like they do with Boilies in fresh water. Otherwise my short-shanked hook is fed through once from side to side. If you do decide to strip off the legs then spend some time peeling a couple of joints and use them for tipping off other baits. Use your imagination and think like a hungry fish!
The only time I cut a crab up is when it's a very large softy or if i'm after flounder (mind you they seem to be able to take in a huge bait, given the time!)