This sounds less safe because you'd need to wake him up to torture him into insanity. If you wanted the multiple layers you could torture the obliviated version into insanity, but I think I prefer the transfiguration. I'd even consider making it permanent with the Stone of Transfiguration, but this would result in a lot of lost knowledge and it's also possible that the horcrux network would consider it a death.
ETA: I rather liked the wand-in-a-dementor-pit idea.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 114, and also, as a special case due to the exceptionally close posting times, chapter 115.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)