I suggest you reconsider any shark dive uses chumming and feeding to attract sharks. These operations end up training the sharks to relate food and divers and create a harmful pattern for both sharks and divers. With some training, choosing the right location and conditions sharks and divers can coexist without the use of cages.
I have personally been less than 10 feet from Pacific Black tip and White tip while in Bora Bora and while at Disney’s Epcot I experienced their tank dive with a Tiger Shark. We are not in any sharks food chain and they don’t want to attack us unless we teach them to associate humans and food. Please look into Project Aware - Shark conservation for more information.