I want to get some more inserts so that I can put more in my pocket diapers for night time use. Should I just buy extra inserts or buy doublers (i'm not sure what the difference is, to be honest!). Also, what kind should I get? I hear lots of people talk about using a microfiber insert and a hemp one together. Any reason? And if so, does is matter which one goes on top (closest to the baby)? Thanks!