On 2010-04-04, JimT wrote:

I have doubts roofers would approve of the metal ones either as they rest on
the shingle. They have a more visible profile too. The plastic ones lay flat
so, on my house, you can't see them at all from the street. I'm "pleased"
with the results. If their was ANYTHING wrong with them SWMBO would make me
do it over. I'm well trained that way.

I beat those metal ones flat so I could tuck them under the shingles.

It looked pretty obvious stuff would pile up behind it if left
bent, and I not longer had faith in the manufactures recommendations, so
I just did it the way that seemed best.