I use them all the time. They are actually a go to bait for most saltwater kayak fisherman. Usually you just need 18" from the cork to the bait. You can go deeper if you need too but it becomes a chore to cast the longer the leader. Tie on a 1/8 or 3/16oz jig head and slip on a white Gulp shrimp. Throw it out near oyster rakes, grass lines, or current breaks. After the rig lands rip it hard three times and then let it sit still for a ten count. If nothing grabs it then rip it one more time and let it sit for another 10 count. The sitting part is hard to get used too, but the fish are coming to the sound of that cork ripping through the water and they need a chance to find the jig.
This is usually considered a "gimmie" style of fishing and is deadly on speckled trout. Flounder, redfish, ladyfish, jacks, and blues will all hit the same rig fished the same way.
Just get out and give the rig a decent chance to work. Chances are you'll put fish in the box!!
2012 Hobie Pro Angler 14
2 Ron Chapman Cottonmouth pirogues