"Aquaplane speed is a function of tyre pressure and speed and weight has no effect ..... "
True, but pressure is dependent on tyre air volume which is dependent on tyre profile which is dependent on weight.
That is, the firmer the landing, the greater will be tyre distortion from max volume, 'round' profile. Hence the pressure will increase and aquaplane speed will be higher.
As the wheel spins up, centrifugal force will tend to restore the round profile and lower the aquaplane speed. How much depends on oleo pressure which depends on weight which depends on.......
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The bloke who ops for a greaser rather than a positive touch down on 'the spot', is generally the same bloke who does not have an issue with not using full runway length for takeoff.