.
Looking good...
Instead of using a piece of metal to stiffen up the skirt, try adding another layer or strip of coroplast.
Just buy a spray can of permanent contact glue. Coat both surfaces, wait for it to tack up and press them together. Done.
Pay attention to the direction of the coroplast tubes. If you line up the tubes in each layer it will be easier to bend in one direction
If you alternate the direction of the tubes in the coroplast it will be much stronger but harder to bend. A example of that type of construction would be a sheet of plywood.
By using coroplast instead of metal, you lessen the chance of causing damage to your vehicle or another vehicle should it fly off. (tires, paint, glass)
>