I think what screws me up is when you get a super low number, you can skip a shot and then numbers come up. So there's got to be some immediate impact of a reduced dose. What am I missing?
Can you point out an example? I'm not sure exactly what you mean here.
As far as this morning, you've got 2 factors you can control that influence blood sugar - well 3 if you count exercise. But for your purpose, you could control his insulin dose and his food. In your situation this morning, I'd have changed the food rather than the dose. Once you get into using the Petsafe autofeeder (which I absolutely LOVED) you'll have more control over when he eats when you're going to be gone.
With the food, you can control the volume of food, the carb content and the timing. Which of those things does what with a cat is going to be individual - so you'll have to tinker around and see how he responds to each of those things.
For today, if I'd seen the +3/148 and knew I was going out, I'd have put food in the autofeeder to open at +5 and put a larger quantity of punkin's regular low carb in it. I could count on him always having an appetite because of his acromegaly, so I had total confidence that if there was food in the feeder, he would get it and eat 100% of it.
Some cats aren't like that - for example some cats will just graze and nibble at their food. For a cat like that you might be able to put down a dish when you leave and you could count on the kitty eating a little here and there over the next hours. On the other hand, some cats will ignore food and just nap - I'd be more worried about a cat like that eating when you wanted them to.
If it had been a more significant drop at +3, say 100, then I'd have used a higher carb food because I knew that punkin's nadir was pretty regularly at +5.5. I might have fed him at +3 as well, and set the timed feeder to open at +4 and +4.5 as well. Molly/Skooter bought 2 of those feeders - I wish I'd thought of that when i went back to work. My husband and i went a bit crazy driving back home from our jobs to check on him more than a few times.
If the preshot were really low, you always have the option of skipping the shot too. Safety has to come first, so whatever you think you have to do to keep him safe.
I wouldn't have reduced his shot last night to be gone for a few hours today, however. You might find some other tips that are helpful in the sticky about working and following Tight Reg.