John when you said he was getting into the kibble with his numbers going into the 300's that would be normal. That is what I took with his numbers being in the 300 but from what I can see his numbers come down really good with his insulin so to me that means his insulin is keeping working at the dosage you are giving him. Now don't quote me on that because I am still learning about what numbers are good and which aren't.
When you mentioned he was getting into the Kibble have you thought about slowly transitioning your other baby to canned food? In the long run it would be better for them both and at least that way, you know Wilbur will not be getting into the Kibble.