it's pretty heavy duty leather, not going to break
I 'knot' the pouches by quite simply doubling over a length of cord, tying that into a basic knot to form a loop at the end - don't make it too small. I then melt the free end of the cord back into the knot.
The loop is then passed through the holes in the pouch and the cord is then passed through the loop and pulled tight. IF you work the sides of the loop round the tabs so it's not pulling directly upwards, it looks better and is stronger.
You need to punch the holes in the pouch tabs far enough down so that the loop can grip the sides.
This holds the pouch more centrally and is about as strong an attachment as you can get.
It's much quicker and easier to do than it is to describe.
I've been thinking a bit about slinging heavy objects and olympic sports.
Slinging a heavy object with just the one arm is daft. It would make much more sense to use a larger two handed sling. Wrist loop on the retention cord and a solid toggle or handle on the release cord.
Using a style similiar to mrboss or a hammer throw would let you use much larger weights and sling them much further - albeit with reduced accuracy.
Whether or not this was ever done in battle - no idea, but it makes more sense for the hammer to have originated as a sling missile rather than the far more complicated weight with attached handle that could be thrown back at you the same way you threw it at someone else.
5lb would still be a good weight to sling with such a device - but given that it's done mostly with straight arms and anchored by your whole body weight - I reckon you could sling 10lb plus quite easily.
It would be interesting to make a heavy duty staff sling and see which is more effective. That or a two handed sling.
Any indications of two handed slings that you've come across thearos ?
I'm thinking that if there are ancient depictions of hammer thowers, maybe they were not hammers but large slings.
Just a thought.