My cat has diabetes (Luxembourg)

Hi everyone,
My cat has been recently diagnosed with diabetes, i'm kindda new with this . He is getting his insulin shots 2x a day, i also changed his diet. The vet recommends me Royal Canin for diabetics. But real protein like chicken is much better for him . Any suggestions or ideas how to deal with diabetic cats ? Is homecook meals much cheaper and safer ?

thanks
teri