RE: Plasticized dope mixture
the talc and dope should be like cream, not thick like whipped craem but like cream straight out of the bottle. I would never use sanding sealer (Dope and Talc) over any open frame covered surface. If you do, then when you are sanding you will surely cut through the covering at the ribs. Also it is not necessary, just lay on enough plasitcised dope to get a shiny finish. Lay it on with the brush held almost parallel to the surface
Regards