Zoom GHM-1 Guitar Headstock Mount for Q4 Handy Video Recorder

I picked up one of these Headstock Mounts thinking it would be good for using my GoPro on my ukuleles and guitars. Out of the box, the design and feel seems to be pretty good. However, the first time I mounted it on a headstock, the plastic part of the Thumb Knob broke - just split apart. I'll try to superglue that back together later, but since I have extra thumb knobs I went ahead with trying it out. Using my GoPro Hero3+ with an open-frame mount, I attached to camera to the pin joint on the GHM-1 headstock mount. The fit is extremely tight, but can be accomplished with plenty of patience. Once mounted, I found the angle was too shallow to really get a good view of the fingerboard, so I added three extenders. This gave a slightly better angle, but still not what I was hoping for. At this point the whole mount system is getting pretty heavy, and I am concerned that the clamp might mar the finish on the guitar headstock. I'll continue experimenting. First impressions - Not what I hoped for, but worth doing the experiment.