To summarise:
Descending at same (Cl/Cd)max AoA at whatever speed is required to achieve it: No difference with change of mass.
Descending at a standard descent schedule (e.g. M.82/290KIAS/250KIAS): Lighter ac descends at a steeper rate as it is no longer operating close to (Cl/Cd)max value of AoA.
[ 19 July 2001: Message edited by: BEagle ]