we are presently building a new coker, I have talked with 2 crane vendors and both recommend 2 cranes for reliability . Make sure you have a maintenance area for working on this equipment. In the electrical room for the resistors banks make sure you install an overhead trolley beam for lifting as they are quite heavy. always keep a spare crane bucket as these are long items for repair. make sure your lifting cables have the plastic coating increases relability
have you considered automating the crane operation?