"1) my understanding is that the likelihood of having a downswing of X BB increases exponentially as your winrate decreases. Can any math guys confirm or deny this?"
playing with the numbers on the website ggbman linked (
http://www.reviewpokerrooms.com/poke...uirements.html) it seems that it is close enough to linear for reasonable winrates. heres the numbers i plugged in.
bb/100..roll
0.25....1941
0.5.....970
1.......485
1.5.....323
2.......243
3.......162
4.......121
i used 5% risk of ruin.