I may be incorrect so I apologise if that's the case. I definitely read that there is a more suitable knot and found a tutorial but I did it during a desperate time and didn't keep the links. It may be that the knot is more suitable to partial where a slipnot is more suitable to full suspension. I suspect I found it in the resources section but maybe not. It's a real simple knot and it was literally a picture that showed a number of steps. I'll do a quick search and see if I can find it.
Okay, I must apologise. Having done a bit of back tracking research I realise my error. What had read is that many people assume that the hangmans knot is needed for hanging when in fact the slipnot is much more appropriate. I made the error of getting the two knots mixed up. So it is in fact the slipnot that is best and its the knot I made my attempt with. It's a much simpler knot to tie than a hangman's knot. I think this is the image I referred to.
I didn't find it came undone at all. I was attempting patial but managed to somehow get out of it after things had gone black and I'd started convulsing. I remember being somewhat aware of what was happening in my periphery. It wasn't a pleasant experience and I soon realised I wouldn't be able to go that way without experiencing some significant discomfort.