On a safety note, if the clamp does snap, it's likely to do it when you're riding, and you don't want a part like that dangling from a cable and going into your spokes. If the clamps are aluminum, spreading them isn't a good idea. I'm not saying this will happen. I've heard of success stories with people doing exactly what you're trying. However, if you're serious about sticking with the drop bars, that setup is kind of a cheapo stopgap measure. I'm willing to bet sooner or later you'll want either bar end shifters, or integrated road levers. You may want to do yourself a favor by not spending your money on something that isn't a long-term solution. That's my $.06.