A:AnswerGen 3 & 4 ring sizes are not the same. This might be because Gen 4 is smooth on the inside. You need to order a new size kit for Gen 4, or find your size in the store.
A:AnswerIt looks like it don’t does it at night while you sleep, unless I am just not looking in the right spot on the app. But I don’t believe it does daytime
A:AnswerThe materials used in each finish are different. You should look at Oura's website to learn exactly what materials are used. With that being said, the gold shows scratches more easily and I would recommend against it if you have an active lifestyle.