
Hello and welcome. Max looks like a real snuggler.
We take the dose of the existing insulin in mind when switching insulins, so that would be somewhere in the 2.5 to 3.0 range, as 3.25 units of Prozinc got him too low. The reason I am hedging what to suggest is your night time testing. Is there a reason you do not get tests at night? Many cats go lower at night. We determine how to change the Lantus dose based on how low it takes the kitty. Plus some cats react strongly to an insulin switch so you will need to switch when you can monitor closely for a few cycles.
Make sure you read all the Sticky Notes on the top of this forum. Especially the one on dosing methods as people here use one of the two dosing methods described in that Sticky Note. Keep asking questions as we love to help here.