Designing an optimal keyboard layout for 1-finger use

This experiment builds on my past project that analyzed 9 million Tweets: http://ktype.net/wiki/research:articles:progress_20110209

So technically the headline should be 'Designing an optimal keyboard layout for chatting in English using one-finger, using data from 9 million Tweets'.

Any idea how it compares in speed and accuracy with Dasher? http://www.inference.phy.cam.ac.uk/dasher/