HA!  Funny you should ask.

Based on statistics, we hit the first block at 30% variance but the pool was running for several weeks below 500MH. Small hash rate and you have a better chance at hitting in the low percentage but it takes longer.   Then we hit the second block at 53% variance and over 1 GH in 2 days.   Now, I'm taking the curve and estimating to about 75%-80% any moment now for the next block.  As we get closer to 100% variance after each round with more hash power quicker we will hit the block.  Let's see how close I am.  Notice the variance is climbing much faster now with higher hash power.