Aoa.
I have not designed lifting hooks. However, in principle, design of hooks and lifting arrangement should be done in a way, similar to the design of a steel frame. (Deciding a suitable layout for the lifting device and hook., calculating total load to be lifted, determining members, welds, and stiffener sizes , depending upon load distribution to various members and joints...)
Design of these lifting devices and hooks, is generally to ensure safety of work people during construction. In USA, generally, OSHA regulations provide basis for the safe design of these devices.
A good search on the internet might help you collect specific details relevant to your requirement.