We had a long discussion about this on a diabetic listserv to which I belong (subscription only). I have had two diabetic cats in my life; lost one almost 20 years ago. Lost the second just a month ago; she snuck out somehow and disappeared.

She did well on the diabetic catfood; I understand some cats won't eat it. Her dosage shifted constantly, and when she developed neuropathy I knew it wouldn't be long. A big jump in her dosage reversed the neuropathy but it was always hovering there. She could walk but not jump.

Good luck with it all; nothing you decide is wrong and nothing you do or don't do is wrong. -- MA