If two tie-downs of the same type and capacity are used to restrain a load in a given direction and one is longer than the other, the longer tie-down, with its greater stretch potential, will permit the shorter tie-down to assume the majority of any load that may develop.
How can you possibly tie down an irregular shaped object with tie-downs all the same length, angle, etc?
The 744 freighter tie-downs I've seen have no strain gauges fitted to them, so tightening them all to the same value would not be possible. And as soon as the aircraft pitches or rolls, the forces on the tie-downs would also vary.