I can't remember the guy's name,Sean McEntee. OK, fine. (Dan's post collided with mine), but someone on this forum showed pictures of a build; he sticks down his silkspan (or polyspan) with clear, but after that he puts white dope into his clear. It's something like 10% to 25% white. So by the time he's ready for his base coat, the plane is already mostly white, with little weight gain over all clear.
You'll need to search around for the rest of the details, or hope that someone comes on and coughs up the rest.