Sorry you didn't get a faster response. One thing that may be helpful is when you post here, then post in the group too with the link to your post here so it's easy for people in the group to find your post.
Looks like you're starting to get some slightly better numbers so you're doing what you should be doing!
I see you're feeding a little of the Dr. Elsey's kibble. Even though it's low carb, some cats react to it like it was high. I don't think it'll make a big difference, but if you could remove even the little he's getting for a couple of days, it would answer that question for us.
As long as he's eating kibble, even low carb, you have to use the Start Low, Go Slow dosing method. That means holding the dose for 7 days. If you hold it longer, that can sometimes allow glucose toxicity to start (basically, the cat's body gets used to being in those numbers even with insulin).
You do test more than enough to do Tight Regulation, but he would need to be on canned/raw food only, so not even the Dr. Elseys. TR gives you the option of increase as often as every 3 days if the dose isn't getting the results you want. It's a more aggressive protocol but also gives the best chance at remission.
Here are
explanations of both of the Lantus dosing methods.
Hopefully, some of the other members and Mods will be able to help you too. I saw some tagged above but I'll add the other 2 Mods,
@Marje and Gracie and
@Sienne and Gabby (GA)
In the meantime, as long as he's got access to the kibble, keep increasing by .25 every 7 days until you start to get some mid to lower blues (then you might need to hold the dose a few days longer).