Wow, 99, that's one late suicide. The problem is we don't know what he was on and of course his age obviously meant he must have been very fragile anyway. I did read about one person on this forum who posted a while back about adopting such a position, but I think they were banned, so not sure if they succeeded. They seemed confident about it. I suppose anyone position is made better by going into it quick, which is of course mentally more difficult. I can imagine that the body would find it harder to recover from such a position though, as well as being more comfortable.
Obviously bodyweight wouldn't play much of a factor at all. So it might require a little more fortune when it comes to compression.