Does your cat have diabetes?
I think they generally use Lantus for cats, right? I think they traditionally only used basal because their diet is primarily protein.
None of my cats has diabetes but I know people who care for D cats. Getting the insulin dosing right is very challenging since a visit to the vet’s is stressful for most cats anyway.
This is the type of insulin my petsitter used for her D cat:
ETA: Thomas received 2 doses daily, after meals. I had to give him his injections when she was away one weekend!