Well, you can calculate it fairly well. By some bizarre act of statistics the GSIH win rate/standard deviation ends up looking alot like a
very good limit players.
I got something like 6bb/100 win rate and a 36bb/100 standard deviation. bb = big blind.
If we plug these into
BruceZ's formula for bankroll using a 0.1% risk of ruin we get:
B = -(36^2/12)*ln(0.001) = -108*ln(0.001) = 746bb.