If you need to send a part out to be built by a professional shop, a good drawing, well identified, is essential. The KISS principle applies, and be sure you don't request closer tolerances or more exotic materials than you really need, or it will cost you.
If you want sound and long-lasting fabric covering, proper shrinkage is essential. And an accurately calibrated iron is a means to that end. Ron Alexander details the process and offers tips on how to avoid damage to the underlying structure during tautening.