I just made muslin #8 and totally messed it up. I tried to do a minor narrow back alteration. Bad move. It deepened the wrinkle at the underarm. Upon reflection, it makes sense. The directions for the first narrow back alteration cautioned against making an alteration of more than one inch. I am so frustrated. I'm going to go ahead and make another muslin using the full length of the dress. I shortened the back at the waist (it makes sense - I did it on my skirt sloper) and went back musln #6. I think that's the best one so far. At this rate, I'll have a dress to wear for Christmas. Sheesh! Scheherazaad recommended tweaking the back at the zipper. I'll incorporate that change too. Stay tuned!