My 9x9 tarp only works on my 11 foot hammock when turned on the diagonal because an 11 foot hammock has a 9 foot ridgeline and you need rain coverage on the ends. So the perfect tarp is (to me) 8x12 or 10x12...that way it doesn't require the diagonal hang and gives maximum protection. Other than that, an 11 foot hammock makes a tremendous difference. I am sure a 12 footer would be even nicer, but you start to limit yourself with hanging options and tarps at some point.
Things I notice with longer hammocks:
1) Less calf pressure. It matters. Get the sag right, though.
2) Can manage with narrower hammocks. Add to the length and you need less width.
3) More storage area in the hammock. Takes some ingenuity but there's more dead space at the head and foot.
4) An 11 footer that's four feet wide feels a lot roomier than a 9 footer that's 52 inches wide.
Can you make a hammock too long? You have to get a diagonal lie to be flat... at some point, hammocks become too narrow to be used on a diagonal. At some point, hammocks become too long to be made wide. There's the weight factor. To get a 12 foot hammock to weigh the same as an 11 footer, you have to reduce several inches of width. When you do this, the lie becomes less flat. Or the hammock becomes heavier as an alternative. Then you have to carry a longer, heavier tarp. Then you have to deal with trees farther apart. It starts to limit you.
Everyone has a different belief. I subscribe to the 56-inch-wide and 11-foot-long theory of the perfect hammock. 52 inches wide for ultralighters...But that's just my belief. Plenty of others exist and no one is wrong. HYOH.
Now carrying the Mini Tattoo Stove!
Light weight. Low prices. Great gear.