I do not know the A/C differences between 747 Classics and 747-400s...
And yes, I know that bringing temperature to please everyone is not easy.
A few pointers, with my experience of 747 or other planes...
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(1) A cold-soaked cabin is difficult (impossible) to bring back to acceptable (warmer) level.
(2) A 747 cabin can be cooled (to freezing) using 3 packs, but uses extra fuel.
(3) To save fuel, generally 2 packs only are used. Does not cool as well.
(4) To bring temperature down (daytime) close all window shades on sun side.
(5) To keep temperature up (night) close ALL shades, especially with few people aboard.
(6) Each human body produces the equivalent heat of a 100 watt light bulb.
(7) Cabin zone temperature (in the old 747) can be difficult to control.
(8) Cooling cabin of a plane parked long time in the sun is not easy. Close ALL shades.
xxx
In the old days, we were told to keep 68ºF (20ºC) in the cabin, later became 70ºF, then 72ºF, and now even to 75ºF, especially when passengers are asleep at night. This is obviously because of fuel economy.
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There are passenger regional differences too. North American and North/West Europeans seem to prefer cooler temperatures, whereas South Americans, Africans or South Asians do not mind a couple of degrees higher. I am certain there may be differences of company policies depending where the airline is from.
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A confidence...
With PanAm, we had a "cabin temperature adjustment" knob in the cabin for flight attendants to regulate the temperature + / - 2 degrees... I was told (later) that the knob was "NOT WIRED" to anything. It was a flight attendant "pacifier", so to avoid their frequent visits to the flight deck to ask the flight engineer to adjust cabin temperature. Makes me laugh. Keeps Suzy happy.
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Wait until our cabin attendant friends read about that...!
Happy contrails