I have the 9 footer, and 12 footer. From the few times I had hung, here is my take on it.
9 footer, is good for warm seasons, and shorter Hammocks.. EN Single.. In diamond set up mode. Covers just enough, to keep you dry and light breeze off yea.
12 footer.. covers EN single, And my DL 11 foot Hammock.. in Diamond mode. good coverage.. Tried the square mode but Rain was hitting the last 5 inches on both sides of the hammock. back to diamond mode. :-)
For the cost, I might seek a 16 footer so I can go Square mode, and have doors & keep the high winds & snow from coming in, and keep temps tad warmer..
I plan to do some winter camping with the 12 footer.. to test it out, in snow storms.. with Vehicle with in reach.. and keep the 9 footer for summer good weather use.
That is my limited use and skill level thoughts on it. They are nice tarps..