In my experience flying the 747, I would adjust the descent point depending on weight. Bgin descent earlier for a heavy airplane and later for a light airplane.
With landing weights varying from 630K down to 400K on the -200's descent rate can change considerably. So (generally) fly the same speed and vary the descent point according to weight to fly a flight-idle descent (ATC/traffic permitting). My game was to save fuel by managing energy. FMS VNAV descents are another story.