We used this style structure last year, with 30ft long arches. This year with a reduced camp size and after learning much at last year's burn, we are downsizing to 20ft long arches (middle height of 6ft, ground dimensions of 27ft X 10.5ft)
-light to transport
-we didn't have PVC raising up off it's rebar stakes (rebar was 12" long, with 6" in the ground and 6" sticking out) last year, though the tarp was staked down with its own pegs and that may have helped
-pretty easy to set up
-gives you lots of space underneath
- you get a lot of shade coverage out of it (minimum top and 2 sides if you take the tarp to the ground)
-in my opinion gives you a happy middle ground between too rigid and too loose, if done right.
No so good things:
-does indeed balloon like crazy. Guy lines over the tarp are necessary.
-Especially if you go with a larger shape, you need some rigidity between the arches (or as I call "ribs") along the apex. We tied rope along the arches, knotting at each rib, but the whole structure still moved and swayed back and forth. This year we are switching to X shaped crossbar attachments, and joining the apex with 3ft lengths of the same piping.
- we are using bungee balls this year, to attach our aluminet along the front and back ends of the hoop
- we will be roping guy lines over the tarp to reduce ballooning, and securely roping the other ends of the tarp to the both piping and pegs in the ground. There will be 2 rope lines coming out from each end arch to the ground.
- switched to aluminet tarping to allow a little more airflow, and ordered it to perfectly fit the dimensions of our structure (last year's was too big which resulted in some bad jimmy rigging)
As others have said bring double to triple ropes, pegs, etc you need and go nuts with securing everything.
Last year's not so well rigged shade: