For the drakes, I'll flock the whole thing grey over grey rustoleum for a first coat, then the head and back all the way through the tail and femoral tract with black over black rustoleum. A second coat of grey over the area you want white. That gives you a double coat which is important to durability. Then paint over the grey area with flat white and paint the head part behind the eye and back of the head with white, likely you will have to paint the head white twice. Paint over the rump and tail one coat of flat white and it will leave the area behind the wings a nice light grey.