Here is the difficulty in us recommending a starting dose for PZ without seeing any data at all. I understand you haven’t been testing due to your vets’ incorrect info.
Most cats do what we call “bouncing” which means if the BG drops low or fast, the liver releases counterregulatory hormones to bring it up so if the vet tests when she’s bouncing from a low, they will continue to raise the dose.
When stating you could start her at the Caninsulin dose or a little less, I mistakenly thought you had home testing data but since you don’t, it is safer to start her at 1u twice a day as long as you start home testing her at every time before you shoot and then randomly a few times in the cycle so we can see what she’s actually doing.
Once we have a few cycles of data to make sure she’s not dropping low, we can fast track the dose up.
A Libre CGM will also help you during this time and give you a chance to learn to home test.
If you need help with the spreadsheet, I can do it for you if you send me a private message by clicking my user name under my kitty’s photo and then “send direct message”.