I've seen the film multiple times, read the book multiple times, and now read that thread you linked. And it's still just plain wrong. What I see in that forum

I've seen the film multiple times, read the book multiple times, and now read that thread you linked. And it's still just plain wrong. What I see in that forum thread is not a sound argument for this interpretation; instead, it's someone proclaiming a theory, getting it shot down and then using ad-hoc immunization and condescension ("that's just what they wanted you to think", "oh, you believe what you saw, poor thing", etc.) to try to puff it up into something respectable. The book makes it as clear as possible that Angier's not using a double in the sense Borden is; he really is getting duplicated by that machine and having to dispose of the results. The film never prints it on screen in big block letters with a signed note from the director saying "this is how it happened, trust me", but it doesn't need to -- it's following the book and doing a good job at it. Thus, attempts to read a "ha ha he really put one over on you" secret into the film are just pointless. (and unless you can show me you're not in the same take-your-logic-and-facts-elsewhere camp as the guy in that forum thread, I'm done here)