You're better off hometesting the blood every day yourself using a human glucometer. The urine strips will show you that there' sugar in the urine, but that's been collecting for hours, you won't know at a specific moment in time how your cat is reacting to the insulin.
If the bloodtest you did in the morning was 350-400 and after a few hours or maybe six or seven since you noted peak, it was 200, your seeing how the insulin is helping your cat at specific times during the day. By charting that information you can better deterimine what dose your kitty may feel best at. Collecting data, the numbers, information on how your cat ate that day, what he ate, was he energetic, happy or tired, all of that can really help your kitty.
What type of insulin are using? What food does your kitty eat? Food is another key part to FD management. Low carb, high protein food can bring down blood sugar and help with regulation also.