Google "Gates Heat Shrink Radiator Clamps". They work like shrink tubing. They will shrink to whatever shape you have. That's the good news. I have used them and I like them. I have no leaks! The bad news is they are pricey, and a one time use. Add to that ,when you need to remove them, you should have their special tool, or you will cut the hose in the removal process. Ask me how I know.
John