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Throughout, I refer to photos of real wolves or dogs to see where each of the three colours should go.
Not sure if these would help or if they're anywhere near the standard you're looking for, but I would use the same techniques on Alsatians that I use on wolves. After a white undercoat, I wash them in GW's Agrax Earthshade (dark-brown wash) then drybrush them white. When that's done, I apply a thin wash of watery buff or bone paint down the back and sides, and maybe over the paws too. Then I add a slightly narrower band of reddish brown (GW's Mournfang brown, heavily thinned with water) down the back. Finally, I use some watery black paint to create a narrower stripe still down the spine.Throughout, I refer to photos of real wolves or dogs to see where each of the three colours should go.It's a very quick technique; once you've done the 'preshading' with the wash and drybrush, it only takes a few minutes to apply the three colours.
I'd say before you begin painting a dog, particularly a large one, you should sedate it thoroughly; and a muzzle would be wise too.