RE: What to do I use to seal Polyester material?
The thing I liked about the Stits system is that it is all polyester based. Dissimilar materials tend to have issues, especially as they age. If your using full scale products your probably a lot better off than buying the stuff sold at the LHS.
I know there a a lot of guys that have never heard of Stits and the airplanes I have seen that have been finished with it look really good and hold up really well.