Don't worry, Steve. You have the best tool at your disposal for handling Oreo's glucose levels. It's called insulin! Oreo is actually doing very very well on such a small dose of insulin and once you have the food thing sorted out and get more comfortable with lower numbers, you will be able to manage it. Feeding small meals and keeping him hungry is important. When you see a steep drop like you did at +3 last night, I would immediately feed a small amount of medium carb food to prevent a steeper drop and then you might not have needed to resort to HC food. Numbers in the 60s and 70s are safe numbers. We generally reserve HC for numbers under 50. Has someone provided you with this bit of reading?
https://www.felinediabetes.com/FDMB/threads/8-10-tashie-pmps-high-questions.101989/#post-1087990
It might help for you to look at other kittie's spreadsheets to get some perspective on the idea that this is a marathon, not a sprint. Take a look at Ruby's 2020 tab when she was first diagnosed. She was in much worse shape than Oreo, but once I found this forum and started following TR, she got regulated within 2 months but still experienced some lows that scared me a lot at the beginning. Then she flattened out nicely until steroids came into the picture recently.