Just my opinion....
Why not take the cowl with you to the automotive paint supply, some NAPPA, auto parts stores mix auto paint, they will be happy to assist you and see that youll need a more plyable material for the "flexable" cowl.
Automotive paints are usually expensive, however, the amount you need should be the min. which can be accurately mixed, I think one quart.
Hopefully someone else will chime in and be of more help than myself.
This probably worth what you paid for it.
Have a great day.
Roger