We used the newborn RealNappies on Chelsea and didn't need to boost them at night because she woke up every 2-3hrs so just changed her then. (In fact she still wakes up every 3 hours lol

) She was quite tiny so doubt extra padding would have fitted her little bottom anyway. But if you didn't want to change the baby every few hours you could use an extra booster, personally I'd use the prefold against baby's skin then the booster underneath but either way would be fine (except microfibre of course)