It appears that vets like to start a lot of cats at 2 units. That's what our vet told us too..
Have you switched his food recently from any dry food/kibble to an all wet diet? If you swap out all of the dry food, or once you wean him off of it his numbers might go down with that alone. Kibble/dry food is very high in carbs.
If it were me, I'd probably stick with 1 unit for the length of the dosing method you've chosen (although I don't see one yet). You'll want to decide which to do; SLGS or TR because that's what you use to decide how often to change your dose, up or down.
https://www.felinediabetes.com/FDMB...-low-go-slow-slgs-tight-regulation-tr.210110/
Typically most people start with SLGS until you can get more comfortable with testing and seeing what your kitty is likely to do.
Please, please whatever you do, get a test before EVERY shot. And get a test before you go to bed - if his numbers are going down and it's bedtime, you'll need to find a good movie to watch or go to bed and set an alarm...
It's a lot to learn at first...but you'll get the hang of it...promise!