Using Bob Kahns deco strips, I have done it four times, two cars, and never had to anneal it more than just the once. There's not much working of the metal, as you only bend it once. The awkward part is dealing with the long curved deco without scratching it while you finish the second end. It is a challenge, but they really do look nice.
For those who obsess about exactly how their 356 left the factory!