David, the whole point of this process is to eliminate all the dope and filler steps. The SLC takes the place of all that.
I now use Microlite film instead of SLC, and need no paint at all! Pretty good selection of solid and transparent colors are available. My Ringmaster is covered that way and has survived a pair of inverted landings on asphalt with no damage! Also, the finish has stayed wrinkle free in hot sun and car storage.
By bonding the film to the fiber you get a composite material with better characteristics than either fiber or film alone. And, it is a really lightweight finish that is quick and easy to do.
If you do want a painted finish, the SLC is primer ready after a light scuffung with a scotch pad. No base coats and filler required.