Hi Hawk,
We never really need the wipers above about 210 kts (clean speed) because at higher speeds the rain is blown away. Also above 210 you are not usually at a critical phase of flight for looking out of the windows, ie near decision height or below. If it is raining then you are generally heads in flying on your instruments. I have tried to park them at higher speeds to stow them a bit lower down, but they usually end up worse perhaps because of the increased aerodynamic load. BTW they are so incredibly noisy and distracting most people prefer to leave them off unless the view is really impaired. Great pity they are withdrawing the rain repellent, that worked a treat and was silent.
S & L