As you ex-PFO'rs have probably read, I did a lite study on SD vs number of LHE tables being played at once. For each extra table I play, I found my SD goes down, reducing my variance. Of course this only works to a point, and after that point, it goes way up, with a corralating drop in WR. This leads to a weird paradox. Eventually, my Required bankroll (RBR) to play a given lilmit drops to the 150-180 range, but the minimum buy-in (MBI) for 8 tabling is now 240 bb's. I now have to play with more bets than I need to. This is mainly due to a decrease in FPS due to the ABC style I am more forced to play at 8 tables, rather than an increased number of hands. Graph stolen from an other thread of mine:
Ok, back from that psuedo hijack.... SD can be thought of as your 'luck' factor. The smaller the number, the less luck affects your results. So with a style that has a lower SD, your results tend to stay closer to your expected WR.