I have braided LOTS of cables in the past, from 24pin atx extensions through to the little motherboard speaker!
The best thing i have found to use is 550 Paracord, which can be picked up for around a fiver for 50ft of it.
The coverage it offers is unrivalled - *completely* and its very easy to work with.
It is however very snag prone but a bit of practice works wonders.
Sleeving a 24pin ATX extension can be time consuming but there are tricks i picked up along my way.
Paracord does not stretch, at all lol.
*Cut the cord
longer than required, possibly to the point where you think its a touch too long.
*Remove the pins from the female end
only (on the 24 pin)
*Slide on your pre cut heat shrink, then your cord.
*Slide the cord half way along the cable, position your heatshrink in place, and heat it - Yes, the process does seem odd, but bear with me.
*Once its sealed and cooled, firmly hold the un corded cable and the heat shrink, and twist in one hand, as if you are spinning the cord around the cable. this will break the heat seal between the heat shrink and cables protective covering, once done, push the shrunk heat shrink down as far as possible, now you have one side sorted.
so, we move the the other end:
*Push the rest of the cord onto the cable - fully, then add your heat shrink. position it in the required spot, heat it, job done - cable sleeved.
Doing this method allowed me to sleeve a 24pin in less than 30 minutes - start to finish.
I also used 2 straightened staples, with the top 1/4 bent over to form an L shape, and a pair of needle nosed pliers.
tools i used.
Female connector end
Male connector end
Was this one perfect? not exactly, it does take some getting used to but its easy enough to pick up.
Another thing i would heavily recommend is to strecth the end of the heat shrink