You have a valid question....
I have also seen this, but somewhere I saw where someone put the adjustable loop onto the hammock side. For someone using a tree strap / marlin spike / toggle arrangement this is a much better idea. I have found that when I went back to adjust my sling after a bit of time in the hammock, the adjustable loop that was wrapped around the toggle knot was difficult to work with. When the fixed loop is put on the toggle knot, it is very simple to adjust the sling because the adjustable loop slides easily through the rigging on the hammock side.
Originally Posted by rubicon1
This is also going to require that the fixed loop be slightly larger to make it easier to put onto the knot produced with the marlin spike / toggle. Your mileage may vary depending on the width of your tree straps and what you use for a toggle.
One draw-back to this process is that the extra length of the rope coming out of the whoopie sling no longer acts as a drip line. You may need to add a danglie something to route any water running down the rope away from the hammock.