The amount of garlic and thyme you put in a 7-quart slow cooker with 2 large roasts depends on your personal taste preferences and the size of the roasts. However, here's a general guideline that you can follow:
Garlic: You can use 4-6 cloves of garlic for a 7-quart slow cooker with 2 large roasts. Peel the cloves and chop them finely or crush them before adding them to the slow cooker.
Thyme: For dried thyme, you can use about 1 teaspoon. If you have fresh thyme, you can use around 3-4 sprigs. Alternatively, you can use a combination of both dried and fresh thyme to enhance the flavor.
Remember, these amounts are just guidelines, and you can adjust them according to your taste preferences. If you prefer stronger flavors, you can add more garlic and thyme. It's also a good idea to season the roasts with salt and pepper before adding the garlic and thyme to enhance the overall flavor.