We have a down hill called Rocky Horror that is loose as hell and steep. A nice intimidator. Sadly I know what you mean mate. Eat a lot of roost videoing our clients on the tracks. When in the fun stuff I usually drop back or lead out so I have clean video of the obstacles and any of my screw ups ahha
You might want to move ur gopro to under the visor, I had to many ripped off the helmet and have moved mine and never a problem any more plus easier to tell if its on from the beeps. Even easier running the Garmin Virb XE.