I've tried it a few times and had no success. As soon as I try with anything but my hands I can't get enough compression. I'm sure it is possible with very careful positioning of the bags/socks and things but I just can't seem to get it right and get frustrated each time they moved. When there was also the potential for everything to move again once I lost consciousness and cause me to fail I just thought it wasn't worth further effort when partial hanging could do the same thing with a bit more control.
But then partial hanging wasn't as easy as I thought it would be. I had decided to do it but them because SN seemed to be highly thought of I thought I'd try that first and resort to partial if SN failed or I couldn't get it. I had left my rope all set up until someone made an appointment to see me so I took it all down. I managed a couple of times with partial to get almost blacked out, and it wasn't a bad feeling but I've had a much more pleasant feeling when testing night night with my hands.
It was the possibility of failing with lasting problems that helped change my mind too. I read that a full recovery will be made with SN so I though, perhaps stupidly, that I'd just try SN and if I woke up later just do some more or then just do night night or partial again if I could. But upon reading about SN more and realising the correct context with failing SN is that full recovery is possible with medical intervention, which is why I said perhaps stupidly because now I realise it is obvious that lasting damage can occur because you are still starving the brain of oxygen and decent blood, just like with night night, so now part of me thinks if I didn't now have the SN to try night night as much as possible first or partialand after a proper attempt, go with SN. I just think blacking out from night night or partial and then coming to again could be the least traumatic experience of all the methods failing. Dunno why I think that, I suppose it 'feels' like there is less direct damage being done by the actions required to attempt.
This is just my thoughts though, I don't think I'm as knowledgable as most others here so others could probably give a more solid basis for their decisions.