Did you know, the new GH3 battery grip relocates the tripod mount to the right side? We're not talking millimeters here, it's way off to the right. This new position can be highly problematic as it will throw off the optical center of your lens when you want to mount your camera to rigs, and use matte boxes, or even follow focus systems. So one solution is to just not use a battery grip, the other is to use an adjustable 15mm baseplate like Stewart Eastep has shared. [Thanks Stewart].
If you need to get proper alignment back on a set of 15mm rails, check out a few of the adjustable baseplates on the market. Here Stewart is using one of the CAVision adjustable baseplates which offer up/down as well as left/right adjustments found via B&H (click here).
CAVISION Adjustable BasePlate with 15mm Rails