I can't speak for the larger version that VXfan is working with, but I find that the "mere mortal" size that I've got (weathertec), work best for keeping rain out when I've got the window cracked a couple inches to vent out smoke...yeah, I know...
(mr mackey voice on) smokin' is bayud m-kay?...
VCrossfan, I lke the looks of where you're going with these...
Just a thought, maybe experiment with a heat gun, to get the radius of the bend closer to the same...
I know, they're kind of expensive to be experimenting with like that, just my two cenz...
