I haven't been too impressed with videos I've seen from bike-mounted cameras unless they were on a smooth track. For anything bouncy, like dirt, you need more shock absorbsion. So mounting it on your body, especially your head, works better. Personally, I prefer the rider's-eye view of things. Did your "killer-deal" GoPro come with a bag of mounts?
We are talking about semi-permanently affixing a mounting plate on your helmet, which you may or may not approve of. I have one on my MX helmet but not my full-face helmet.
I have a chest harness, which I had high hopes for. Unfortunately, it's so low as to view through the windscreen, which gives a very distorted view.
Good luck with your mounting options. Anything RAM-Mount must be awesome