When I look at the SS, I don't see anything that makes it obvious that the insulin is tapering off in 8 hours. What I see is a kitty whose numbers were all over the place when he was eating dry food, who had some really big drops on relatively low doses of insulin. A 60% drop on one unit, or going from a black to a yellow, is pretty decent action. I also see days where the PMPS is significantly lower than the AMPS that indicate to me long duration, not short. I keep reading lately about how short a duration Prozinc has, but I'm not seeing it as often as I am reading about it. Prozinc isn't "PZI". Compounded PZI
can last less than 12 hours, as little as 8 in some cases. Prozinc tends to last longer.
But like others have said, that was "dry food" days. Now with an all canned diet, while the numbers are not "non-diabetic", they aren't out of control either. You can see that his body is doing something to fight off the carbs and the boosted BG from the eating. Not enough, but something. Otherwise he'd be sky high after 48 hours with no insulin.
I think I would hold off on the insulin until you get to a point where you are able to monitor a whole cycle, and then start with a low dose and see how it works for a couple of cycles. Basically, like Kim said, you're starting over. You've removed the the thing that was most likely the cause of the ugly numbers. Not sure what others are thinking dose wise, but I'm thinking maybe .5u to start?
If I were in your shoes, and Bob had good numbers like Smokey does right now, I'd be jumping up and down doing the happy dance!
Carl