deepfat

You might need to make the mountings pretty sturdy, probably better to the car than the bonnet. I was driving mine once at about 50/60 in reasonably heavy rain and noticed the rain going up the screen, when it was safe I turned the wipers off briefly and the airflow kept the screen clear. I know very little about aerodynamics but it suggests to me that there is quite a lot going on at the base of the screen hence I think anything flimsy might have a short lifespan.