Shed roof design

Hi All:

I have been lurking here for a while. Lots of good information.
It seems my searching skills are lacking when if comes to roof design.

I am building a 8x12 shed. I have been thinking that a pent roof is the best way to go.

My question is, what would be the easiest roof to put on? I am thinking a corrugated metal or fiberglass roof. But I am not sure how far the panels should overhang the exterior walls. Or how to keep rain from blowing in the sides of the panels, or other tips I need to consider.

Can anyone point to a discussion that covers these type of questions?

Thanks