Elf, leeries and cob will all use different rigs. I'm not experienced in sliding so won't help you there, but for casting out a bait just use a polystyrene float or a small balloon (you can put a little water inside too for added casting weight) tied on to your swivel with some floss to fish the surface for leeries and shad. This will only work in clean conditions otherwise your livie gets blown/washed all over the place. For cob who like it on the bottom, use a small running sinker on your mainline before your swivel to keep the mullet or whatever down and a meter or so flouro leader to a circle hook. For elf use a wire bite trace and remember they want to hit the tail of the bait so an extra back hook might help. Leeries want to swallow the mullet or fish headfirst so a thin but strong wire circle hook will be fine, pushed through the mullets toplip/mouthplate, point facing up. Just remember to keep your livie as alive as possible and be gentle with it and cast it gently..ag shame the amount of poor mullets I've gooied off sans a lip, I would feel worse but they just become food. Throw your unused livebait back and keep and freeze dead ones, as whole fillet baits they are also great for shad and cob etc. and sards are costly these days.
Targeting leeries on livebait does take some of the sport out of it (although a leerie on the line is great fun anyhow!) so get some plugs too to throw while waiting for bites and try to take care of the leeries when landing and release what you can for the future.
On a side note, I saw a pic this weekend of a 200+kg raggie caught on a mullet livie put out for leervis on a circle hook and normal monofilament leader and normal tackle. So be prepared, as with spoon and plugs, you never know what might pick you up.