I know it's frustrating to have a picky dog. Especially when you are feeding a good quality food.
Just some observations I've made over the years: Some of the better dog foods, even though they are healthier, are less appetizing to dogs. They just don't smell or taste as good as the cheaper foods. Why? I believe it is the fat content. Fat makes food taste better. The cheap dog food brands use lower quality ingredients but they have done extensive studies into what dogs LIKE. So they spray tantalizing fats onto the food after it is pressed into nuggets.
What makes me believe this? Take a piece of kibble that your dog LIKES to eat and rub it between your fingers or a paper towel. You will feel the grease. Then try the same thing with the dog food that your dog refuses to eat.
You mentioned that your dog will eat the food if you pour bacon grease on it (bad? maybe). Fatty acids are a small but essential part of a dog's diet. Especially for weight gain, coat, and muscle growth.
Either you will have to find a food that Stone likes, or fiqure out a way to make his current food more appetizing.
We make a homemade 'wet' dog food that we add to their dry kibble. You could also make a gravy. We make our food from ground deer meat, brown rice, eggs, celery & carrots which are pureed with beef broth. The carrots color the food orange (lol). We have also substituted potatoes & sweet potatoes instead of the rice.