If you are wanting the hives for honey production then you have but one real decision to make. Put another brood chamber on now or wait. If you wait and they back fill too much into the brood chamber it will cause your hives to swarm. If you decide to put another brood chamber on now, make sure you checkerboard it with your current brood chamber to get the bees to recognize that they have more space. Getting more bees means larger work force and more honey production.