On the 67, X-sync is 1/30. In leaf shutter mode, the flash sync cord is connected directly to the sync socket on the LS lens, not the camera.
With regard to the focal plane shutter/leaf shutter relationship: wWith a leaf shutter lens attached and leaf shutter mode engaged, sync must be reduced to 1/8 on the camera side or it will not synchronise with the leaf shutter (half frame banded/unexposed). Another point to make is that MLU cannot be engaged with the 165mm leaf shutter lens.
Be aware that if the shutter speed dial is set to anywhere between actual speeds ("blank space") a mirror hang situation will arise. Only use the marked shutter speeds.