It looks like you switched Rudy from Tiki Cat to Arcana. While they are both low in carbs, the Tiki Cat is zero carbs and the Arcana (at least the one variety I looked at) is 7%. That shift may explain some of the higher numbers. Some cats are exquisitely sensitive to carbohydrates. If I'm remembering, the Tiki Cat is also quite low in calories. I didn't think to look at how that compares with the Arcana. I'd just make sure you're thinking of calories and carbs as different. You can feed Rudy as much low/no carb food as he wants and it shouldn't have a big effect on his numbers unless he is truly very carb sensitive. However, if he's gaining weight on a very low carb food, you need to limit his intake due to calories intake.
There are two other points that come to mind. Insulin needs change. A dose that was good last week isn't great this week. Your dosing strategy has to follow what the numbers tell you. In addition, holding the dose if the dose isn't getting numbers where you want them may not be a great idea. In Rudy's case, it's hard to know if you need to hold the dose or increase. Given that he hasn't seen green numbers in a while, you may need to increase his insulin. Remember, with Lantus and especially with TR, you base your dosing on how low the dose is taking the numbers.
The other observation is that you weren't able to get PM tests for over a week. You don't know if numbers had dropped and if what you were seeing during the AM cycle was a bounce. Just as an example, the PM cycle on 4/22 looks like Rudy's numbers were dropping. He started at 321 at PMPS and by PM +4, he was 234 and at AMPS the following day, his BG was 137. His numbers were dropping throughout the evening cycle. By PMPS on 4/23, his numbers were back at 300. He bounced.
I'd also like to make a suggestion. You seem to be on top of the basics. You may want to consider posting on the
Lantus board. The board is as busy as Health -- there is usually someone around 24/7. Some of the members you're already familiar with also post there. There is a huge amount of expertise that is specific to Lantus available there.