Just about anything that swims will eat a half bait. The main thing you need to keep in mind is that you don't bury the hook point and barb inside the bait. Position the hook so that the end of the hook is near the end of the bait and it has only gone in halfway to the body of the bait. Secure it by two to three half hitches around the tail.
Snapper, bream, a variety of reef species, trevally, flathead, kingfish, mulloway, gummies and rays love pouncing on a well presented half pilchard or pilly.
Even though this rig is dedicated to using either a half pilchard or garfish, it can be used on any baits that have been cut into half, including whitebait, mullet, herring, slimy mackerel, squid and so forth. The main thing that you will have to change when using this rig is the size of the hook that you are going to use, which will need to match the size of the bait that you are using.
As an example, I would use a 3/0 to 8/0 size hook with half a mullet when targeting snapper or mulloway, while for bream I would use a 1 to 1/0 hook in a half pilchard.