In my experience, you want your walls/ceiling to be neutral and if you have white, you can actually use those surfaces to bounce light when appropriate. I've always had white in my studios. Expect to paint it frequently, especially with Berners .

As for what colors work best with your dogs, they have similar color combination to my Rotties with the addition of white and I've found virtually all colors work with the Rotties. My favorite is black but I've used warm browns, blues, white of course, and even mauve and all have worked just fine. In general, Fall colors work well especially gold/brown combinations. Check out some of the major publications and see what combinations work best for Berners and then add those colors to your backdrop collection.

Good luck. Would love to see pics when you're done. Must be nice to have the room although I'd like at least 20 feet of length for multiple dogs.

Jim