A most efficient layout on a six-person Catan game

A few weeks ago, we were playing a six-person Settlers of Catan game, with our usual friends and one friend's parents. A six-player game can, of course, lead to rather an over-crowded board, but as we progressed through the game, it seemed that nobody had run out of building spots early on.

It wasn't until about half-way through that I suddenly realised what a remarkably efficient layout we had managed to produce:

Quite by accident, none of our settlements was directly opposite another on any hex. So, theoretically, we had the maximum possible number of building spots. Blue, green and orange had all run out of new spots by this stage, but each had managed six. Red had six already, and one more. And there were four remaining spots which could be accessed by either white or brown.

As it happened, the game did not continue for many more rounds after that. Here's the final board:

I think it was Richard (red) who won, with the largest army (or perhaps two victory points) as well as ten points on the board.