Interesting indeed. Perhaps what is confusing us is curlycords location. In the US we are used to a rating like CMP for plenum cable. You suggest using FT6 anyway, but frankly that is a waste of money if the plenum rating is not required for the installation.
It must just be a difference, but most of the hundreds of department stores we deal with have a high ceiling, and many times the drop ceiling is 30 feet up with an open space above that for ducting and wiring. If the wiring is above that drop ceiling, there is no real advantage to conduit. It is much more expensive than properly supported cable runs or cable tray and makes moves/adds/changes more costly. If the ceiling is exposed, then certaily conduit would look cleaner. Your conduit from the telecom room to the jbox should be sized according to how many runs you are placing in it. It is pretty routine here to have a minimum of one 4" conduit from the telecom room to the floor area.
Installing a conduit system for the first time in a large department store is certainly not a beginner job. Hopefully this guy has a trained crew available to do this installation so it is ready to be cabled when done.
Good Luck It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com