When you need to get a bait down but still have it swim free, adding a split shot is the way to go. The split shot can be anywhere from right up against the hook to 3 feet above the hook. Different placements of the weight can create different presentations. Most of my luck has the weight between 6 inches and a foot of the hook. As a general rule the bigger the bait, the bigger the split shot needs to be. A live shrimp or small minnow needs a 1/8 oz split shot while a live mullet or shiner would need 1/4 oz or even more.
List other fish you have caught using this rig.