So I thought I'd do some pics of my method for an easy soft shackle.
Only tools needed are a standard fid (or anything to push on tail through the other rope), a knife and maybe whipping twine and a needle.

I also like the two 'arms' method as you get less of chance of picking out threads where you open the loop up to open the shackle.
I also find it chafes better and is easier to close the loop.

Firstly, cut a piece of dyneema the diameter of tge shackle you want x2, plus 2 x 300mm tails.
Find the middle and mark. Then mark the two points for the size of the shackle.

The using the fid, pass one tail through a point just off centre to the centre mark. The tail you pass through should be from the long side, yellow in this case







Pull through so loop I'd around 4 times the diameter of the rope


Put the two tails between the fingers on your non dominant hand, with the length marks at you fingers


make a loop in yellow and roll over green




Put the yellow tail between you ring and little finger.
Then take the green and take it around the back of yellow and in front of the loop, pulling the green through a little and passing through that as it goes over the loop



Remove the yellow tail and tighten all slightly. You should have a figure 8 or diamond shape



Take green around the back of yellow and up through the middle hole



Now this is the tricky bit, to do and explain!!
Take yellow around the back and behind green (where it comes out of your hand) before bringing up through the hole




Now tighten and you will have to work shackle 'arms' through a bit to get the length right.
Once length right, tighten a lot!!


now with the tails, you can use a hot knife like I have or if you don't have one, whip the tails together. This stops the getting frayed and messy