Steve,
It would be most interesting experiment to determine if you can get back into polyphasic without the ramp up. I recall a discovery special or such which outlined how the brains of spacestation visitors had a heck of a time learning coordination in microgravity - and some trouble adjusting to gravity again when they returned.
The interesting thing was that after the first trip - they could re-adapt in minutes. Not that they were consiously doing this. It's as if thier brain just loaded the right program (saved from the first learning experiences) for the right environment.
A friend has terrible trouble sleeping - tried everything. He cant go polyphasic as a final solution - but if it can be a learned program that can be used in an otherwise monophasic pattern, as you've described, it may be valuable. Thanks for that.
This was the 'year later' blog post that had enough synchronicity to have me join your forum. So for what it's worth - why dont you give it a go and see if your an astronaut