Mozella
But I got the idea the theoretical 747 example was free of such constraints as well as ATC restrictions, but I could have misunderstood what was being said. That's why I asked.
Not theoretical...real world. No speed brake, power off descent compensating for wind, weight and airport arrival pattern, adding power at ~1,000' AGL, if left alone by ATC, which obviously wasn't always the case.
If flying an airplane where the variety of broad landing weights was not possible, then the weight factor for descent planning was/is negligible and unnoticeable.
To be clear, at same Mach/airspeed descent schedule: heavier weight...longer glide. Lighter weight...shorter glide.