Well it's always hard to judge how much one handful is, because we don't all have the same size hands. If he is eating it within a couple of hours, I would say no, you are not feeding him too much. I might even suggest you might want to up the amount you are feeding him.
As long as you are providing a nice, large enclosure for the baby to walk around in and get exercise then you're not feeding him too much. Put the feeding station way at the other end of the sleeping site so he has a long walk in the morning to get his food. Then give him enough food that there's always some left over.