Like glauco and melloa said - this guide is a joy, and makes resolution of a common but technically demanding problem accessible to new users. It's got good coverage of the necessary background, warnings, precautions, exact commands and what they actually mean, and details for understanding and executing this task, which is essential since something like this can go so wrong if misunderstood by a user not highly skilled in the arcane aspects of FreeBSD hardware commands. A lot of this info also isn't collated anywhere else either, as far as I can tell, and not as neatly. This may even be worth updating and expanding.
I would also like to say this is a very well written article. As a newbie to FN, I have been able to answer most of my questions by just reading. The resources on this site have been invaluable to me:)