Four years later.... :D

 

I think the Tuning Chris uses in the video is Open G.

 

First Chord:

 

D---0--

B---7/8--

G---0--

D---9--

G---9--

D---8--

 

This sounds exactly like the Chord Chris plays. I haven't figured out all the other chords, but you can slide the neck up or down and will find one or two chords that will also fit to the song.

is it Em D/F# Cadd9 G

easier version from me