This is an awesome post. The one thing I wish it included was context around their lifestyle during this time period. How many hours a day did they devote? Were they working full time? If so doing what? What other responsibilities / life things got in the way.

It's one thing to imagine yourself doing this given six months of dedicated time (not that they claimed to have had this) and another to get a real sense of how one might fit this into one's life. Anyway, great, detailed article and an impressive accomplishment.