Welcome! We'd love to help you and Buttons. First, I'd suggest you read the Protocol and Beginner's Guide. They are on the top of the forum and in my signature in blue. You have a nice mild insulin, which is the first step. What does Button eat? We feel strongly wet low carb food is best. A vet explains why here:
www.catinfo.org. The final step is home testing. We think it's imperative to know her levels before you give each shot (to be sure your dose is a safe one) and then check mid cycle to see how low the insulin takes her. It sounds like you are planning on that too. Wonderful!
It sounds like you are giving insulin only once daily? ProZinc is dosed twice daily. If not, what can happen is that the levels drop after the shot and then, after 10 hours or so, steadily climb until the next shot 24 hours later. It's important to have her in lower ranges for as long as possible so her pancreas can heal.
We have a spreadsheet similar to the one you used in 2012. The directions are here:
http://www.felinediabetes.com/FDMB/threads/fdmb-spreadsheet-instructions.130337/
Be sure to use the world version (it looks like you are outside the US?)
If you like, post daily with her levels and get advice on dosing, and support. Check other's threads and spreadsheets to see how the insulin is working for them. Ask all the questions you like.
I have not heard of a connection between cataracts and diabetes.