I'm so sorry that you are having all this trouble with purchasing the Trilostane and trying to get Junior's cortisol at an optimal dose.
Could you find out what stimulating agent the vet is using? With his numbers being indicative of Addison's you are absolutely doing the right thing in taking him off the Trilostane and having those electrolytes checked. A dog in an Addison's crisis wil have increases in drinking and urinating. How is his appetite? Any diarrhea or vomiting?
Keep us updated, ok
Hugs, Lori