[kach22i]

I like the cardboard creation, the slight deflection up angle is nice.

Adding a splitter in a second step or phase would be nice, and it might even add strength is done right.

One material for consideration is thin PVC sheets, I think my sample is somewhat cellular and has some weight to it despite being thin. I have not used this on my project vehicle, purchase it for large scale modeling that takes advantage of it's floppy character and ability to bend. I'm not sure what happens to it below freezing though.

Certainly finding the best and most cost effective material is important.

My experience has been that if it looks vulnerable or frail it will be an irresistible temptation for some idiot to test it out by backing into it with their car for kicks when you are not looking.

Good luck.