The Banknotes are Air-cushion + Aristocrat. v6 are Magic finish + Aristocrat. Finishes do not affect stiffness or thickness.
In fact, aside from how they feel on the surface, there should be no difference between the Banknotes and the v6's.
The Vortex will be slightly stiffer than the v6's because there is less ink saturation, but it does also use the magic/aristocrat combo.