I am not sure there is an easy answer to this, does anyone else find that once you get over 140mph the wipers become partially useless and its even better to just turn them off?
The airflow up the screen catches the blades and separates them from the screen. Nothing much you can do about it, though on the upside you don't need them and the air carries the water up and over.
I used to have some louvers (Painted Red) on my wipers on the old Capri Mk 11, I think that might improve things somewhat by putting air pressure on to the wiper arms to keep them from lifting off