I really disliked the Fuzzi Bunz as well. You should sell them if you haven't yet and recoup some of your investment. They do hold their value pretty well. I got $10 each for our FBs. Some people love them! My sister in law used them on her twins from birth to potty training and she was thrilled w. them.
It doesn't sound like it would work, right? But it does! Try looking up BumGenius Freetimes or G Diapers and you'll see that it is basically the same concept. I do think that the tri-fold method works better on older babies and that wrapping the prefold around the baby first is likely better in regards to containing things w. younger babies who are still exclusively on formula or breastmilk. I agree w. Flick about watching diapering videos on YouTube. There are loads of these! Many ladies have spent many hours videotaping themselves folding and pinning diapers around dolls. It is a weird thing that this exists, but it does and it is really very helpful.
I watched some of the YouTube videos. They were helpful. This one shows 5 different ways to use the prefolds. And, her baby, Noah, is a champ as a model :)
Here's the link in case anyone wants to see it: http://www.youtube.com/watch?v=JDqa45EOHfE
I don't know why this didn't occur to me before, but I just measured my prefolds so that I could tell you what size they are. Anyhow, they are about 12x17. They were probably a little bigger than that new, I think they shrink when you wash and dry them the first time? Lev was 28lbs and 33 inches long at his 15 month checkup and I checked and can still snappi them around him, though I prefer the trifold method. We tried these out when he was much smaller and just folded down the front of the prefold before snappi-ing it back then. So I think they can be pretty flexible.