I would go with the number plate one before I would use the kind your talking about. I have a story that may change your mind. My buddy and I were in a desert race and he had a fuel bottle like you describe mounted on his handlebars. About 5 miles into the race he noticed it was gone. Didn't even notice it had fallen off, but he thinks it happened in the whoops. After the race he got another one, it lasted till the first time he went over the bars, he hit with his chest causing it to open and dump gas on him. He bought a larger fuel tank after that. They don't stay on very well when you have something in it. I had the number plate fuel tank and it worked pretty well.
Pat