An authentic tuning derived from Judaic worship music, where the instrument was used to accompany the singing of the Chazzan, also known as a Cantor. This style of tuning uses the Chazzanut mode.
Starting with the bass (largest strings) tune as follows: E F G# A B C D E (Ahava Raba mode)
In the early Middle Ages in Eastern Europe, the secularization of the Jewish worship music gave rise to Klezmer music. Jewish troubadours, known as klezmorim gave the music a place in weddings and other simkhes (joyful events). The Klezmer music eventually blended with Slavonic, Greek, Turkish, Gypsy and even American jazz tempos and rhythms. For Klezmer music try the Misheberakh mode which is: E F# G A# B C# D E
Two alternative tunings that work well with singers comfortable sing in the Key of G are (again bass to treble): E F# G A B C D E (Natural minor) and D E F# G A B C D (E is tonic). Notice, in the second tuning, all the notes are the same but you're starting on D rather than E. Includes tuning tool.