On my Trillium
I have an 8' foot rail and I bought an 8' awning
. However, though the bag is 8' long the awning
is actually closer to 7' due to the room on either side of the bag to allow for space while rolling and the zipper ends. I mentioned in a post I had on this that I felt I could have gone with a 9' awning
and had the 6 inches hanging off either end as the actual awning would be fulling attached.
I have a few pictures where I show this here: