I use those toppers when switching food. I only use about 1/2 of one of those little cans. So far I've Nature's Variety about the best for everyone to like. Before Grains is good to mix in as well. I wish more cat food makers made the bigger cans. Pet Valu's brand is in a bigger can but Bobee will throw it up. Wellness too, but no one really likes it. Nutrience is one of the few better ones and they have rabbit in a large can. I'd love to make my own food, would have to be cooked though. I think the biggest problem is they get used to that don't have to chew it texture and if they have to chew something they don't want it.
If I ever start out with kittens again, they're getting raw from day one!