You are right to gradually change your dog's food as he makes the diet transition.
Along with the signs you previously mentioned, there are also several other characteristics that are directly linked to a dog's diet that you can watch for:
Diet directly affects your dog’s skin and coat, weight, energy level, and gastrointestinal function. If a problem occurs in one of these areas, it may be linked to improper diet.
Watch your dog’s response to the diet over 4-8 weeks. How does her coat look? It should be shiny and free of flakes, but not greasy. Have you noticed a change in her energy level? A decrease in energy could indicate a problem. Has she lost or gained weight? Obesity in dogs is a very common problem which can often be reversed with proper diet and exercise. Excess weight loss may occur if your dog does not find the food palatable.
If her response to the diet is poor, it may be time to look into other foods. A sudden change in dog foods can cause diarrhea or even vomiting, so switch over gradually unless otherwise directed by your vet.
That being said, it is also important to note what ingredients you are planning to use for these home-cooked foods. Although many commercial dog foods can be unhealthy for your dog, not using the right ingredients when making home-cooked food can be unhealthy as well. It would be helpful to research healthy recipes for home-cooked dog food from reputable sources, such as this Making Your Own Pet Food article.
It is also worth mentioning, as with any health-related questions regarding your animal, if you have any questions/concerns you could bring them up with your vet on your next scheduled appointment.