Oh, *that* one. :)
Ah! I never drive less than 40km/hr. (Don't aske me how I get in and out of the car. )
USan product; didn't remember where you were (until I just read your use of kilometers). It's pretty...er...slick, no pun intended. You probably have access to something like it.
Perhaps that's why I don't have the trickle-down issues you do...even at low speed, perhaps the water's ending up where it's not available for dribbling down the glass in front of you.
If you have an equivalent, there, it's worth a shot at US$3 - convert as needed - a bottle. I did all of my glass with it, and probably have half the bottle left.
Mine uses 22"/560mm driver's side and 19"/475mm passenger's side.