After trying the toggle, whoopie slings, UCR's, plus the original Hennessy Hammock Figure 8, I went with this.
Here is what I went with for now. Here's is the parts.
6' Amsteel (7/64) Locked Brummel on both ends
Dutch Whoopie Hook (Slides freely on 6' Amsteel)
6" Amsteel (7/64) Locked Brummel on both ends.
6" Soft Shackle
Here's how I have it set up:
Tree Strap & Dutch Ti Clips. A Dutch Whoopie Hook (Slides freely) on a 6' Amsteel with 2 locked brummels (Eyes) on each end. One end is Larks head on to the loop of strap. On the 6' Amsteel I have a 6" piece of Amsteel with 2 locked brummels attached by a Klemheist Knot. (This knot holds tight, but is easy to move up and down the line to adjust) I use a Soft Shackle to connect the 2 eyes. It works faster than my UCR and the weight is the same, minus a few grams.
I set this low to start, marked the line and no movement. Moved it up until it was way over what I would hang in real world. Only then, I noticed less then 1/8 of movement, but it held. If anyone is interested, I'll pop some pics up later.
I should add, the only real con to this setup is the amount of splicing for both sides. 8 Locked Brummels, (On a few of them, you have to make it where you only have access to one end) and 2 soft shackles.
For large full resolution pictures of each part click here: http://flic.kr/s/aHsjDZXG8v