If the rest of the world wasn't so rigorously attached to monophasic, I don't see why it would be so difficult. It's not an inherently unworkable schedule, it's just that our work, commerce, and socializing all take forms that don't accommodate it.
Anyways, I'm intrigued by what he calls the "Everyman" schedules - they seem like a compromise between the rigid Uberman and the monophasic that the rest of the world uses.
It's difficult because our bodies did not evolve to sleep to that schedule. Every account I've read concludes with "It's great! I'm happy with how it turned out! Oh, by the way, I don't do it anymore because it's so hard to keep up."
Read the thread I linked to, which is now at the bottom of this discussion.
