Everyone talks about the Carthy tuning CGCDGA, in fact the top string is often tuned differently. As he explained on the Homespun Video, he started trying DADGAD and it didn't work for him – this may be to do with his vocal range. Anyhow he basically took DADGAD and shifted it over across the fretboard – look at the notes on the 7th fret. Starting from the 5th string, you get EADEA and he added an E to the top, giving EADEAE, you just need to alter the 2nd and 3rd strings from standard. He played around with the bass and top strings so he could move easily into DADEAE or DADEAD. He then decided to drop the DADEAE tuning by a tone to CGCDGD. He modifies the top string to A or B and can easily change it to C or D depending on which key he's playing in. I think he uses either DADEAE or EADEAE on Cold Haily Rainy Night and a few songs from the album with Willie's Lady and Bonnie Lass of Anglesey. He uses heavy gauge strings because he's tuned so low; with light gauge strings they're too loose and he couldn't get the powerful bass. I agree with DGCGCD tuning for Famous Flower.