We do know that the YJ-18A and CJ-10 (and maybe YJ-18C?) are hot-launched, which means that a thinner outer ring spacing inside the 850mm UVLS cells that must be included in order to act as an exhaust channel for the missile booster's hot exhaust to vent through during the missile's launch from the cell.
Hmm, wasn't CJ-10 never integrated with UVLS? I seem to remember there was some discussion awhile back on the subject.