My method,since 1954, is to apply 3 or 4 coats of clear to the wood, sanding each lightly, then applying damp silk span to the wing, using thinned dope to adhere the silk span to the structure, rubbing the dope in with my fingers.. Pulling the silk span gently to remove wrinkles. Do the top then the bottom on one wing, then do the other wing. Let the silk span dry, I like to leave it over night, then apply one coat of thinned tautening dope, followed by 3 or 4 thinned coats of non tautening dope. Exact same way I apply silk..
Polyspan goes on dry, as it is a plastic, SHINY SIDE UP, heat shrink very carefully, apply tautening clear, then follow on with non tautening. Has worked for me every time.
At times, just before laying down the silk span, I have applied a quick wet coat of dope to the root area of the wing, but not the rest, This was to make sure the silk span stayed in place as I pulled it
tight along the wing.
Your method will come from experience, not from others, as a lot depends on the dope, silk span, size of the structure, type of structure,etc. In other words, what works for you.