(Correction: This review should be for the 16', we also bought this 11'5", same princible, there's a third diamention to consider.)This is working out great for us. Cuts the heat off the deck considerably but allows plenty of light to shine through.
You'll have to get creative with the installation process. I used bugee cords to connect to rain gutter spikes, then roped the single side out to a tree. It flexes a little, and will sag some at different times but then retracts again.
Very big at 16 feet end to end, the third side is about 13 feet out to the tree. Because it's a triangle it still can allow unblocked sun to shine on your plants or even allow your bbq grill uncovered space.
My deck is 15 feet x 8 feet.