Originally Posted by dejoha
Leave the line slightly loose so you can easily slide the tarp back and forth to center. Once centered, you can tighten the tarp completely.
Now, the version with the DutchWare Stingerz/Tarp Flyz, while similar in the basic figure-8 design, requires you to be present at the Stingerz/Tarp Flyz side to make the slide adjustment because once you set the tension on the hardware, you can't slide it any more.
I pictured the line tight and was having a hard time imagining it moving easily once around the trees, even when loose it seems it would grab the tree and not allow for easy movement. But the first video clearly shows you moving it easily so I'm fresh out of dumb ideas. I wasn't able to set up my little test last night but after sleeping on it, I think it makes sense.