I've seen it both ways. Octaves on the lower three and gG BB EE as stated above. Have played them both. Always seemed the worst of both worlds. There's a reason they've never really caught on to any extent.

When touring solo I take a six and a twelve as they voice the same songs completely different. Also, a mandolin and an autoharp, but that's a whole other thread.

As a cyclist I'd compare them to a hybrid...not quite a road bike and not quite an off-road bike. Slow on the pavement and dodgey in the dirt.