Hundreds Vs. David Friedman's Minicity

In Machinery of Freedom, David Friedman proposes breaking down cities into 100,000-constituent minicities.

My first reaction: What about hundreds?

My second reaction: That's pie-in-the sky idealism, thinking that 100,000 people can make any system work.

But I do understand economies of scale, and that 100,000 is much better than 1 million or more, but there is a certain appeal to "hundreds." I don't fully understand the concept, but I'm certain it had to do with a manageable "political" organization, like New England small-town direct democracy, that came very much after the original concept.

Also, my feeling is that "hundreds" would most likely be composed of 100 families, of whatever composition, because the original "hundreds" were composed of only men.

An interesting contrast. Something to look into.