Steve, I think you made the right decision, at least for now, and I think that's a good criteria. Good on you, and my thoughts are with you and your dog. I have heard of cases of feline diabetes being turned around with diet, I don't know if the same can be done in your dog's case.
Also, don't blame the diet -- sometimes diabetes just happens, it may not have anything to do with weight or diet, it might just be genetics. I think (this is not a vet talking, I remind you).
Naaman -- hurray!