The beauty of cigar box guitars is that you can try any combination of strings and tunings without judgement!
In this video, Shane Speal has his Rumbler cigar box guitar tuned to a low Open D tuning (DAD) and talks about the pursuit of creativity.
To do this, use E-A-D strings from a standard pack of guitar strings and tune them DAD. (If you're used to "drop D" tuning on 6-string guitar, you'll slip into this lesson very easily!)
Buy Shane's stubby slide bottlenecks at http://stubbyslide.com
Guitars at http://spealguitars.com