First of all I highly recommend feeding in the cage. The concept of feeding in a separate container is that the snake does not think you are food when you reach into the cage. However, moving a snake after eating causes stress on the animal, and you do not want to move a large snake while it is still in feeding mode. Also when fed in the cage the snake does not associate being out as feeding time. I do not want to take out a large constrictor and have it think it is going to eat!!!!
Hooks vary in size/length-get one that suits your needs. The way I use the hook is any time the cage is opened for handling, changing water, spot cleaning, I touch the snake on the nose, head, or rub his body with the hook. They soon learn that the hook means "no food is coming". Depending on the snake's personality you can then reach in and remove the snake or hook the snake and get him out. The snake NEVER sees or is touched by the hook when food is introduced to the cage.
I have boas, carpets, bloods, burms, retics, anacondas, and afrocks and this hook conditioning has worked very well for me. All are fed inside the cage and all are tame once removed from the cage. Hope this helps-Bill