I'm sorry to hear that Calloway's insulin levels aren't regulated yet. That insulin is expensive! Barney was on Canninsulin and it was pretty cheap. The vet sent us home with half a vial and I think it was less than 15.00. Maybe you could see if another brand could be used that might be more effective for Calloway and cheaper for you.
I have been trying to keep Paddy on a stricter diet and now he is off the Temptation treats altogether and finaly lost a few pounds. I think they are pretty fattening but boy do they love 'em! He loves food so much though that I can give him dry food as a treat because he doesn't free feed so any crunchies are welcomed by him. He gets about a cup in total per day spread out.
Please give Calloway a BIG hug for me.