Ok, so I made a half-circle skirt! YAY
It was very easy, but my waist ended up being like 6 inches too big!
I used the serger to take in the side opposite the zipper, so I now have a zipper on the side and a seam on the other side. The only thing I would change (other than the huge waist I ended up with) is to put my waistband on before the zipper (I mis-calculated so now I have a small gap at the top, need to put a little closure there) but not a big deal. I used 1 layer of material, and used bias tape for the waist and bias tape around the bottom edge because I hate hemming in a circle.
I still don't know why my waist was so big... maybe I left too much seam allowance when I cut it out?
I'll post pics later, my skirt is in the wash now, the non-washed material is kinda stiff.
Thanks again for the tute! You did a great job on your skirt AND explaining it to us!