I use Sig Koverall, on planes such as a Cub that you want the fabric covered look I use Sig Dope to attach the fabric then shrink the fabric. I then apply 4 coats of PolyC to fill the weave. You can still see the weave of the fabric with 4 coats. For a plane that I am trying to simulate a metal finish I apply 6 coats of PolyC then spray high fill sandable primer to finish off the surface then apply panel line and rivet detail. This makes for a very strong, light and durable finish that in my opinion looks better than any iron on covering.
Anthony