my name is Garrett i work for a company called Masterpiece Models thermoforming is something we frequently do. after reading your post i wanted to contact you in regards to your project. is this something you are planning on making more than just a replacement piece for? if so i am positive we can produce these parts for a reasonable price extremely quick. if you are just looking for tips i would be more than willing to lend some advice for attempting this at home. however this process you are attempting undergo requires carefully controlled temperatures and an even supply ot vacuum unless your drapeforming. also from what i gather this part sounds like it may need to be done in two pieces. if you want to send me a pic of the part and give me some more informaiton on your production plans i can lend as much help as possible.
firstname.lastname@example.org hope to hear from you soon.