I tried to think of a way to play this on solo guitar, not knowing where David actually capos, even with the Nashville tuning. This is for a standard six-string guitar. Try this out. Drop the high E string down to D, and then put a capo on the first fret. Play A minor, and you'll get that two-note thing that starts the song. It works better fingerstyle than if you strum all the way through the six strings. Then when you play the E major chord which is now on F, you get an interesting sound, and the same with the G chord shape. Anyhow, I thought I'd post this thing I figured out, and see if you like playing it. I think I'll learn it now.
Matthew