Becky - it is early days for sure. Take a deep breath it will get better, I promise. We've all been where you are right now. I like to say that one of mine bounced all the way into remission. It frustrated the heck out of me but it didn't stop him from getting the result we all hope for.
Looking at your sheet, I think I'd advocate for staying low and going slow. He had a pretty low number this morning and you still gave insulin. You might be in for a big number tonight if he dipped really low mid-cycle. New diabetics are usually advised not to give insulin if the pre-shot number is below 200. Once you have more data and know how your cat reacts then you can start shooting at lower numbers. If he has a history of ketones then that's a different story.
If he were mine, I would stick with .5 units for 3 full cycles before contemplating an increase. Even if he bounces really high tonight. It can take a few full cycles for the bounce to clear. Decreases for low numbers are a different story. You never want to keep giving too much.
Hang in there you'll both get the hang of this really soon.