I'm interested in the vinyl masks. All of the how too, with good useful detail, will help me.

I also was unable to source silkspan in the ultra light grade that I prefer. Actually any grade, not just the ultra light.

You might consider using Esaki Japanese tissue. The latest set of wing panels for my Delta have both surfaces finished in two layers each, carbon tissue (bottom) and Esaki medium (top). The panel is larger than most at 470 squares. Weight gain of the two layers just about ready for primer, has been 35 grams. Of course primer and paint will add 60-75 grams, because of the yellow (worst covering color we have)

Reason for the two coverings is first the wing is built up from sticks and was very light (210 grams), so much so I wanted some resistance to poking fingers through the skins. The two layers added a lot of strength to the balsa skins.