RE: What brushes for dope?
TG, unless you really want the silkspan for the whole old time experience, I would recommend Polyspan or Koverall. I remember a lot of punctures in my old silkspan CL planes, and I would not go back to it.
Polyspan looks a lot like silkspan, but it is a synthetic. It takes dope well, but doesn't soak it up like silkspan does, so it seals quicker. It can be stretched around compound curves. It is not great at going around curves, but I have had good luck with it using an iron and pulling on it. Heat will soften dope, so you can actually iron it over carved wing tips if they are doped first. It is heat-shrinkable, and very tough. It is much lighter than Koverall (although Koverall is not terribly heavy); it would be hard to come up with a strong covering as light as doped Polyspan.
Silk is available, but either you pay for it like gold leaf or you get the pre-shrunk fabric type that is hard to shrink.
Jim