As Mike said, using a curved adhesive mount on the top of the helmet is a great option. I actually prefer to use the helmet front mount though, as it is easier to line up the shot and it gives you better flexibility for the shot you want. They key to a helmet mount is to have the lens lined up exactly with your line of vision, and I find it easier to do this with it mounted on the front. It also makes it easier to turn it on and off. As for durability, I will be honest, I have had a few sticky mounts break off before. This is very rare though. Sometimes when they get incredibly cold, they lose some adhesiveness. Just make sure that you do as Mike said and clean the area, apply at room temperature, and let it set for at least a day. If you're really worried about it coming off, you could tether it to your helmet strap.
Also, great tip for lining up the right shot when using something like a helmet mount is to use your GoPro app on your phone with live preview to make sure that the camera is at the precise angle you want it.