RE: Monokote over silk and dope?
You can get a very glossy finish with dope, but I recommend painting with a coat of Randolph's, Sig, or Brodak butyrate dope, just to soften the existing dope and fill it. I would use aluminum silver as the aluminum fills fast and is light, then I would switch to automotive acrylic lacquer as it is compatible with dope, fills faster, dries faster, and has a higher gloss. Then finish it out with a coat of acrylic clear. IMO this is less work then covering over with Monocote because I suspect you are going to have a hard time getting the Monocote to stick to such an old, not quite filled out silk covering. Because of waiting for it to dry between sanding, it will take more time, a week between each coat or two.