ADAD Tuning is a useful tuning for chord accompaniment on longer scale instruments, especially the bouzouki. It could work for the mandola almost as well, especially if the mandola were slightly longer scale than normal.
The Bouzouki may be strung with either unison (both strings of a course the same thickness) or octave (where the 2 strings of the lower two courses are one thick and one thin). Assuming that the instrument is tuned initially to standard GDAE:
The bouzouki can be tuned GDAE and played like a long necked Mandola. The long scale length makes melody playing a little difficult, but chords sound good.
You can check the GDAE tuning on the Mandola Tuning Page.