I've been beset by problems on our outdoor cycling track in recent weeks and want to protect myself from one particularly troublesome young woman. I have a Polaroid cube camera but, like the Gopro cameras, the housing and mounting are large and obtrusive. I'm looking for the smallest, functional video camera I can use, either helmet, jacket or bar-mounted. I've seen loads on Amazon I'm currently considering. I'm not too concerned about cost, more functionality. Any advice on what to avoid and what to consider?