I would imagaine that you will either be using live sandeel or mackeral, or possibly shads or redgills. With regards to all methods and to keep it simple. set up a running ledger rig with a trace of 15-20lb clear mono of about 6ft in length, on the end use a 3-4/O sharp silver aberdeen hook for sandeel, a 1/O treble for the mackeral and the shads / redgills come ready rigged to be tied on. Out from Swansea with the tide on Sunday you will probably need 5-6 oz weights with 15lb braid, with mono you will need larger weights.
Hope this helps you a little and I have not confused you, It's alot easier to say it than put it in words.
There are many ways of doing this. My favourite is to bind two off, either 4/0 - 5/0 - or 6/0 hooks together back to back. Tie a 6 - 8 foot trace through the eyes of the hooks and a swivel on the other end.
When you bait up, put one of the hooks through the top of the Mackerels mouth and the other hook through the bottom of its mouth. This allows the fish's mouth to open and shut normally.
Slowly drop your weight to the bottom, your weight must always be in contact with the bottom. I will guarantee that the first Bass to see the Mackerel will have it.
How did you get on yesterday?
I was out,but the wind turned the sea a bit nasty for a while and had to anchor in oxwich for a few hours. Managed to catch 1 bass from white oyster ledges 2 1/2lb on live sandeel.