I use the unison tuning GDAD for playing melody and double stop and chordal accompanyment in D and G and some modal stuff on Octave Mandolin. I use a capo for most other keys.
I have never owned a bouzouki, but did borrow one for a while and played chords with it tuned in banjo tuning, DGBD, with octave strings on the two lower courses. On this instrument I used mostly closed chords and it worked well. I found the scale too long for melody playing.