A couple of observations regards how you rebuilt your hubs:
1. A light film of bearing grease is all that is needed. As you noticed yourself, from the factory there was but a light film of grease in the bearing cups.
2. Never take all of the side play out of the hubs as you adjust the cones. Instead, adjust your cones until you can still detect just the slightest amount of hub "wiggle".
Then when you mount the wheel, adjust the skewer so that it just takes the "wobble" out of the hub.
In this way you have the very least amount of side to side tension on the hub bearings and yet you have reduced the wobble to zero. Before doiong anything to the bearings or cones on a hub, I apply a known force to the wheel to make it rotate. I do this a few times and then average the number of complete rotations the wheel makes before coming to a stop. Then I perform whatever maintenance that needs doing. When finished I apply the same exact rotational force and once again measure tha number of rotation the wheel makes before stopping. I have found that by adjusting the cones in the manner I've described, the number of rotations that a wheel will make before coming to a stop, always increases and sometimes by as much as 50%.