I´ve played a lot of shafts in the past (314², Z², HP-II, Revo, WX900)......
I can tell you, the shaft which has the lowest deflection is the WX900......okay, it has a conical taper with 12,0mm G2-Soft-Tip......but it has definetely lower deflection than the Revo-Shaft (12.4) and even lower...