I realized I was wrong about something here. You have to remove all faces with a point in front of them for both 2d and 3d. Minor update to the Prequel Booru page by the way with a few more alts.
I had to learn how to pluralize single letters to write that comment: https://english.stackexchange.com/questions/25277/what-is-the-proper-way-to-write-the-plural-of-a-single-letter-or-a-word-used-as
Small update to add divsel's button, thank you for the follow!