The funny part is: I took notes of the method I used, because I wasn't sure I'd remember all the details (even though, as a relative Bitcoin Newbie back then, I didn't realize the first 2 steps could have been done in one step). What surprised me, is that I doubted the method I wrote down, and not the passphrase:
Another flaw in this whole thing is "inventing your own method". It is never a good idea specially when it comes to cryptography related stuff. There are a lot of things that could go wrong, from small bugs that could not be reproduced when trying to recover to serious bugs that could be categorized as security flaw.