(Marcy uses a substantial rayon/lycra knit and lengthened the dress by seven inches.) I used a slightly lighter weight black/gray stripe for the hole insert and that lead to cutting one sleeve from the same fabric. I had the collar all sewn in a single layer of the gray knit, but it was a bit flat, so tore off that collar and re-did it as standard collar using the stripe knit on the back side. I also used the stripe knit for the faced hem. http://blog.marcytilton.com/?