Two possible reasons for the ripples in my skirt zipper area.
1) The zipper area wants interfacing. I would agree with this one - I see the most rippling on lighter fabrics, fabrics that are substantially lighter than the zipper fabric. Found this in one of the sewing books I got this week for my birthday.
2) http://gorgeousfabrics.com/blog/2011/12/06/there-are-no-hard-and-fast-rules-in-sewing/ Sew from wide to narrow? No rippling? Could it be that easy?
So... the next skirt I make - two changes coming up. Also, I'm going to go back to the overlapped waistband with button rather than the waistband with hook & eye that I have been using. I might also put a waist stay in - my waist circumference isn't very small, and it's more or less the same for 3-4" up and down, so I either have to fit the waistband *tight* (which can get uncomfy) or find my waistband moving up and down at a whim.
Why yes, I have been reading the couture sewing guides. How can you tell? :)