I just finished the McCalls circle yoke dress. The directions for attaching the yoke are ridiculously fussy. Also, that version features a zipper at center back, which does affect the way that you can attach it. Basically, you stitched the facings and yoke together except where the dress attached, then sew the dress to the yoke,, sew the shoulder seams, then flip over the facing and hand stitch it all around. Yuck! I blogged about it http://katiekadiddlehopper.blogspot.com/2009/06/mccalls-5568.html
and my mom added a comment that was actually helpful, so check that, too.