Hello Phil,
Silkspan is a great covering material to work with. Mitch is correct that you will need to build up several layers of dope to seal the tissue. This will give you the foundation to start smoothing out the surface of the silkspan.
I would definately recommend giving a coat of light gray primer after your last coat of dope dries out. This will help you see flaws and imperfections before you start painting, as well as give you a more even surface to work on. It also serves to protect plastic parts from the effects of the metallic paint you'll use.
Just a heads up on using a enamel rattle spray can. (
if you decide to go that route) They can give some awsome results, but the metallic colors seem to take a loooong time to dry. More so than regular colors for some reason. DO NOT go heavy on the paint. Use multiple light mist coats to "build up" the surface. This will give you a more glossy metallic finish, rather than 1 heavy coat.
http://www.testors.com/products/145625 I've used this in the 3oz spray and it works great.
Just like a road map, there are lots of different ways to get to your destination. This is just one, of many ways to get there.
Best of luck with the ol' T-Bolt.
Pauli