Hi Treegal- sorry I haven't used prefolds so can't help much, although I do have friends who love them & use them exclusively. I've watched my friends use them & they seem really easy to put on & my friends are happy with containment/ absorbancy. Another big bonus is definitely the quick drying time.

I think they say to factor in about 24 nappies for fulltime use so that you wash every second day.....obviously buy more if you want to wash less often.

You will definitely be able to use the prefolds as boosters & also what I find with my flats is that they come in handy for spew cloths/ nappy free time/ nappy change time.

Cheers.