I would leave his dose alone and shoot 0.25u in the morning. If you get a number that worries you, post and ask for help. We just have to be so careful with a post-DKA cat who is not eating a ton on his own.
I'm not sure if you saw my earlier post but that's exactly what happened with Mikey. He was a dry food cat converted to wet food, diving, going low. We kept lowering his dose and then Mary took him off insulin just to see if it would work. It didn't. He was in immediately in 300/400 numbers for over six cycles.
We don't need that to happen with Webster. I know this process has been consuming your life and you are exhausted and worried. If we can get him to flatten out, it will be much better for you all and he made big strides today.
If a cat is on all dry and has high BGs, the vet might have them convert to wet and just see what happens in a couple of days. However, alot of vets are just putting cats on insulin, leaving them on dry, and they find us. I haven't really seen that many cats that have a high BG and are on dry and changing just brings the BG right down. They usually need a bit of insulin for a short time. Some longer...ECID.
YOu've got it right so I'll let you get to bed. I hope your wife feels better tormorrow. I'll hang around a few in case you have questions. Night, Mike.