This is just great to hear. He sounds like he's back to his old self and doing fine. I wouldn't be too worried about that pre number either, unless the post number were to start to drop. It seems that the other adrenal gland is producing cortisol and that is exactly what you want.
Good idea to keep an eye on the pancreas and hopefully that won't change. Doesn't seem to be highly likely that it will if it hasn't but ultrasounds are a good idea to keep an eye on it.
Just excellent news for Winston.