A.So far, you are doing a good job and I would not change any of that. The phos-serine you mention almost always comes in a complex formula, and giving one labeled 50 mg is a proper dose. I’ve had clients go up to 100 mg with their dogs, including those that are Pomeranian-sized, with no reported problems.
One form of Cushing’s disease is called atypical, and this variety responds to melatonin supplementation. Specific testing through your veterinarian would be needed to diagnosis if this is the type of Cushing’s your dog has. Another fairly new supplement we’re witnessing positive clinical response with is called Humanofort. It comes in a formula called Dogtor Rx by Pet Equinox.