since 1.5 took her down to 53, I'd go with 1U and hold it for a few days and give it a chance.
Also, she should be getting shots twice a day and it's just as important to test on the PM cycle as the AM (maybe more since most cats go lower at night)
You should test her before you feed her (when she hasn't had any food for at least 2 hours)….You want to know what her blood glucose is without the influence of food.
With Novolin, you Test, Feed, wait 20-30 minutes and shoot so you get a Pre-shot BG that's not food influenced, but then you feed so there's food on board before it "hits" since it's so harsh
Since she's eaten now, we don't know how much of that 212 is due to the food.