Roadies tend to overgear on the track. 50/14 (96 inch) is probably the biggest that most amateur racers use. Most will be closer to a 90 inch gear. 110 RPM average (including the standing start in a 90 inch gear) is what I hit on my latest kilo race (1:18 on my second ever kilo on a standard track bike), and if you look at the video of Hoy (in the fixed gear fever presentation), he is right around that average cadence as well.

Control is a big deal too, depending on the track. At my home track, Alpenrose, most first time kilo riders with aerobars end up riding near the stayers line. While it's not as bad at other tracks (ours is particularly steep for it's length), you'll give up 3-4 seconds with a standard track bar, but you'll sacrifice more if you mishandle even one corner.