I don't know but to me, 2% seems pretty small for sit and gos. It's not unreasonable but I've heard 5% and that made sense to me. I guess it depends on the number of players... but at 9-18 players I think 5% is fine. As well as 5% for NL cash games. I've also heard of 2% for the MTTs.
Of course, all of this assumes you're generally a winning player. Because winning players are the ones who need to prepare for these sorts of swings. I heard someone say, once, that if you're a losing player... you'll need an infinite bankroll to handle the swings.
