Try this site for using dope and silk. I've been going through a covering process on a very light framed WWI combat model. I don't like the "plastic stuff" because I don't like the unrealistic plastic look it gives. I've used fiber glass and epoxy resin on sheeted wings and fuselages and dope and silk on open framework. The issue I have with silk on a light frame is the shrinkage control. It tends to distort light construction. The polyester fabrics (Koverall etc.) at least gives me some control over shrinkage with the amount of heat used in the shrinking process. I have gravitated towards Koverall and StixIt. Works great on compound corners and seems to have a tighter weave than silk so pushing dope through the covering is less of a problem.
http://members.aol.com/GreenHawk/mid...feb98/silk.htm