I would curve the trialing edge up to the fender, gently.
Also, I experienced a vibrating at higher speeds and had to run a thin piece of metal along the bottom edge.
THe material we use is just too flimsy NOT to vibrate.
take alook at my skirts.....
http://ecomodder.com/forum/showthrea...ast-16970.html
see post #37 to see the metal bar I installed.