Does the connection flex between the master and slave fixtures placed in a suspended ceiling need to be supported in any way? It is part of a listed assembly so I would think you would just need to follow installation instructions. Also, I wouldn't think you could assume 3/8 or 1/2" fmc is being used (and thus follow the corresponding codes regarding installation). The manufacturer could have there own unique wiring method not even found in the nec as long as it got the needed listing.
