The photo I used for reference was captured by Jeff Vespa on 10 Sep 2014 at the Toronto International Film Festival. He looks so young, it's hard to believe he was almost 31 when the photo was taken.

With thanks to adamdriverfiles for bringing it to my attention; they are seriously the best enablers.

My best guess is that this took about 6 hours, broken up over the course of a day.

Also on AO3.