Ali, thanks again for the info. I'm feeling pretty much more or less defeated with this. I'm hopeless with a circle skirt. I just don't want it gathered at ALL on the inside. I hate the way it looks and I know it'll irritate me even if no one sees it. All of the hi res pictures showing the edges of her skirt have screwed up the rationality in me.
I'm now thinking of .... and I can't believe I'm saying this... just serging the bottom at a very narrow width and then when I get to the embroidery, just go over top of it. Rapunzel's hem is so flat and flowy that I don't want to actually use biastape cause it'll thicken it up and screw up the flow. =\