Hi Kris and welcome! I see from your signature that you're already hometesting, have set up our SS, and have changed food to a low carb wet food. It looks like you've been tracking to see if the food change alone would be enough and now you're ready to start insulin. So I feel sort of...unnecessary

Just kidding! That's all the stuff we usually recommend in the beginning, so EXTREMELY well done!
Now it looks like Kitty is doing well overall! Those preshots in the yellows are lovely. One thing I want to ask...are you using a human meter or the pet meter? I assume human meter but I want to be sure. If human meter, I'd recommend starting at 0.5 if over 200. If pet meter...same dose but if over 220. We often recommend 1 unit, but since Kitty's numbers are already VERY good, I think a bit smaller of a dose is a good plan. Then if needed, you can raise the dose pretty easily. I'd get a +2 (that means 2 hours after the shot in case you don't know that already) tonight so you can see where she's headed.
A few other questions. Does Kitty have any other health problems? About what time will you be giving this shot? What time zone are you in? We can try to check in on you better if we know roughly when you'll be shooting and since we're in all different time zones, we just need to know which one you're in too!
Please feel free to come by and ask questions whenever you want. Diabetes is tough and though you've done amazingly well already, the dosing part is hard to do on your own. Even when I got comfortable deciding my own dose, I still stopped by daily and reported numbers and asked for advice when I was unsure!