The GH3 is fun little camera so far, but i'm still not super comfortable focusing or stabilizing the little camera just by holding the body itself. I tried putting together a small stabilizer using a few bits from the Prime Rig, and here's where it's at so far.
Without the unique folding hybrid Shoulder/Chest pad from the P&C Prime Shoulder Rig, this little setup would be nothing more than a baseplate and set of rails. Attached under the base plate is the P&C Pistol Grip which makes for a very stable mini gun-stock target stabilizer for small cameras such as the Panasonic GH3.
With these few pieces i'm able to carry the camera with one hand, focus or zoom with the other, and use the wide Hybrid Chest/Shoulder pad pressed against my body for stabilization. The bits and pieces from this kit are all part of the P&C Prime Video Shoulder Rig and one P&C Pistol Grip
P&C Prime Video Shoulder Rig Kit