I only double up the inserts at night.
I have never tried cotton babies inserts, but my ds can go all night in a FB with either 2 MOE microfiber inserts or a joey bunz and a MOE insert. He's 14 months, and not a real heavy-wetter (more of a frequent wetter
) but a single joey bunz or MOE insert can usually last him a few hours at a time
I use one microfiber insert for day, and a microfiber plus a hemp doubler or Joey Bunz at night. Because I have a boy, I fold the hemp stuffer in half and just stick it in the front of the diaper. This works great for us.
I did buy 3 extra microterry stuffers when I purchased my diapers. I have a total of 6 hemp stuffers.
Hmmm... I'd just go for 18! In general I don't double up because my babies tend not to pee at night past 8 months or so. Before then they don't pee enough to have to double up. Most of the peeing is done during the day.. LOL So it really depends on your baby's habits!
We double up all the time now to make the diaper a little bulkier so it fits our thinning down DS better in the legs. We use MOE inserts and for doublers MOE doublers, joey bunz, knitted wool, or kissaluvs super soaker doublers seconds (my favorite now because they are our bulkiest doublers). If you like thin, MOE doublers and joey bunz are both thin. JB are really absorbant. If you use JB with cotton babies inserts (which I *believe* are microfiber), put the cotton babies layer closest to the baby cuz they absorb liquid quicker than JB.
You could always start out conservative and get more doublers if need be. www.fuzzibunzstore.com has free shipping if you need to get more doublers at some point. Also, some people use microfiber towels from the automotive section of big box stores like target, walmart, etc.