1. What if this works in winter?
If you use it in cold weather, you should make sure that your baby is dressed appropriately. Many wearers also like to put a blanket on the seat belt or tie a jacket to the seat belt. In short, you can certainly use the harness in winter, although all seasons are designed to be warmer overall.
2. How does the waist feel after holding the baby for an hour? I want something that doesnt make myself tired.
Does not affect the waist at all. If it hurts your upper back sometimes, adjust the position of the chest clamp to the correct position.