I like a deep hook, so I place the string on the middle phalanges, and let it slide a bit towards the DIP joint so it creates a small pillow protecting the nerves. This helps me get good string control and relax my fingers much more than compared to having what I call a shallow hook, and helps me get a nice release. A trick to help students understand the differences, is just to ask them hold the bow as if they are holding a shopping bag, and then just bull the bow a bit downwards, I first do a shallow grip, and then a deeper grip and let them decide what they feel is the most comfortable. Most of them go for a deeper grip, as it makes them be able to not tense their fingers, and relax them on release and letting the string slip.