Tunings and Strings

Martin & north american Tiple tuning  :

10 strings 4 courses.
Tuned as a ukulele  : Gg cCc eEe aa (G3 G4 • C4 C3 C4 • E4 E3 E4 • A3 A3 ) or one note higher   Aa dDd f#F#f# bb  (A3 A4 • D4 D3 D4 • F#4 F#3 F#4 • B3 B3 )
As a guitar : Dd gGg bBb ee (D2 D3 • G3 G2 G3 • B3 B2 B3 • E4 E4 )
All strings are unwound except for strings 4, 7, and 10, which are bronze wound.
You can find dedicated tiple strings sets from GHS or LaBella

You can also use acoustic guitar strings,
string gauges (from an UMGF paulkris post ) :