"The Fern & Faerie site said to double the rise of your child and use that as your square ... that means I should make mine like 33" square? Does that sound too big?"
Remember that an Oragami-folded flat is going to fit VERY bikini-style, so the rise isn't going to need to be as big as your standard fitted or prefold. The wings will actually wrap over the hip-bone, and meet the front pad at a slightly downward angle. (I'd take pictures today, but my camera is in hiding for the moment - we're moving this week) Davey's a nice tall 30lb 2yo, and we're using 30" flats.
I've been making mine out of gauze I found on the Wal-mart $1/yd table. My last find was pink paisley! :LOL I've been very pleased with the absorbency, and the pins slide through like butter.
I also picked up some Gerber flats to try, since they're just birdseye, and birdseye is absorbent enough. Haven't washed them up yet, though, and they may be too small for Davey - they'll be good for the next baby, though.
Also, I picked up a package of flour-sack towels from WM, because they were SOFT, the right size, and $1 apiece. I have been using a couple already, and they work well if I slap a doubler in 'em.
For flats that end up rectangular, the Oragami fold will still work. Don't ask me how, because my gemometrically logical mind still can't wrap itself around the phenomenon, but my rectangularly shrunken flats fold up perfectly. It's really wierd. I just make sure that the narrower end is at the top when I fold, so I get the full length in the rise.
If the folding instructions look intimidating, try them anyway. I had to play around with it a bit before I got the hang of it, but now it's easy as could be. You just have to get your rhythm down.