The funny thing is when I listened to 'Big Road Blues' it sounded like two guitars, one tuned op a half step and played in D and the other tuned down a half step and played in E. The guy playing in D has a swing feel and the guy in E plays straight. Then I looked at the discography link and found that Charlie McCoy is listed also on guitar. To get that kind of sound on one guitar you'ld need to be in dropped D.