AFAIK the SP was purchased by Charlie Q to serve WLG. I operated it a few times on that run. A real handful because CASA, in its infinite wisdom, forbade any derate so we had full charge with a level off at 3000ft. Fun, fun, fun!!
Then we put her on the SYD-SFO-SYD and SYD-LAX-SYD routes where she was meant to be. Most departures were at gross weight and that lead to a dog's breakfast of fuel feed on the ground. Can't remember fully now but it was really complex for us FEOs with a standard CWT to #1 & #4 engs, inbd tank to eng for T/O to be set as late as possible prior to line up. She also had #2aux & #3aux tanks to keep us on our toes. She did other long thin routes like SYD-PEK-SYD (Beijing). It was common to be at FL430 in late crz. Planning a descent was interesting!
The engines were trimmed to C2 thrust, well below D4 on the other RR B747s so QF had a place to park less than wonderfully performing engines to run them out to overhaul hours.
It was a bitch in the circuit area because of the vast thrust changes available with tiny T/L movements. Very exciting on final!! I got to try it when I re-mustered and did base training - not fun!! OTOH a missed approach was truly exciting trying to get the beast back to normal ROC.
To sum up, the SP did just what she was designed to do quite well. She looked shabby after the need for super long range went away. Always a challenge with such tight MTW and MTOW limits and our lack of day to day familiarity with her.