OK the wing has been stripped, degreased and the frame liberally doped with Nitrate. "Here'smy plan!" : there are a number of techniques I have heard of, but never tried. And one that seems NEVER to have been attempted.
First, see if Nitrate dope really can substitute for Balsarite in adhering iron-on materials. If not, in this case, I can use thinned dope as a backup, since the covering will be Polyspan.
Second, I plan to put SLC over the Polyspan and bond it down everywhere as best I can. Hopefully, this will yield a super tough covering at minimal weight gain.
Finally, the plan is to see how good,and durable a finish can be applied over the SLC. No filler or primer should be needed.
Worst case, is it needs be done over, but at least it isn't my next Nats stunter.