Thanks! The dupli-color shadow I used was a spray and had two cans. The first was the "shadow" to darken the chrome and the second was a clear coat. Each coat of the shadow will make it darker - I used 3 coats 20 minutes apart so you could have it be much lighter (maybe darker?) if you desired.
With 20 minutes between coats, an hour between the shadow and the clear coat, 3 coats of clear coat, and a recommended 4 hours afterwards before re-applying to the truck, I'd advise starting early in the day... mine wound up a little rushed.
I didn't sand or use steel wool to rough it up, just cleaned. We'll see how it holds up.
Regardless of how they last -didn't damage the truck which is the important part. So far I definitely like the look.