Some lighter-duty FELs have only ONE hyd cyl for curling the bucket in the center of the bucket. Heavier duty FELs have dual curling cyls, one at each arm of the FEL. The strongest place to place hooks is directly in front of the cylinders. Two are better than one if you lift un-equally balanced items or items likely to shift, IMO.
I agree 100% with George. If one cylinder, hook(s) in the middle, if 2 cylinders, hooks on the bucket in line with each cylinder. reason being is, most everyone gets a material bucket (though Kubota offers an excavation bucket as an option that is much more robust). The light duty material bucket really is ill equipped to take the stress of hooks anywhere but inline with the cylinders and you could cause the bucket to crack from the stress.