Hi. It's been a while since I came here and was just browsing by. I had some pics saved away on this topic and so I thought I'd share.
I first came across soft shackles when I was a diver. They were useful for light duty applications and had the advantage of not banging around in a tool bag. When I saw them mentioned for offroad uses I was doubtful at first, but then again... I'm always doubtful at first. Nevertheless, I kinda like breaking stuff so I thought I'd give it a shot. Either way, I liked the idea of chucking some weight out of my under-seat bags.
This is 3/4" dyneema rope. You can get it in bulk made in China from a marine supply or pay 5x and get it from "Amsteel". It probably rolls off the same machine, either way.
It's a loose hollow 12 strand braid so it's nothing to run it back into itself in a loop. I don't recall if I used a makeshift fid. I might have taped a pencil onto the end the first time I did one. If you just stiffen the end with a few turns of tape it's probably enough.
You run it through itself and then come back out, then tie a monkey fist and you're done.
I don't know what the breaking strength actually is. As a rule of thumb, a knot has about 67% the strength of the line, but a tight bend can have less, and I have no idea what to say about a clusterific eye splice with the strands wrapping around themselves and taking asymmetric tension. Anyhow that's why I went with the obscene overkill rope size. Of the three I've made, I gave away 1, and I've used the other two on the end of my winch line. I've broken the winch line several times since then. I'm due for a new one actually. The shackles still look fine. They're at least 6 years old now.
What I like about them is they don't tighten up under load. Once the load is off, they just slide open. They work super awesome on cage bars too - something that metal shackles don't handle well.