Ruminations About Fitting, and a New Vintage Pattern!

I am so excited! I purchased my first vintage pattern last week, from karenleanneking on Etsy. It's Simplicity 3562, a 1950s dress and bolero. You have to love those little bows on the shoulders. I'm not usually one for boleros, but I might just have to stitch this one up, it's so adorable.

I've been almost done with the New Look dress all weekend, but I've been putting off the zipper and the hem because I'm a little disappointed with myself. I rushed through the whole thing, and even though I made a muslin, I didn't take advantage of the fitting opportunity it provided. When I tried on the almost-finished dress, I realized that my teeny-tiny changes to the bust didn't really do much. It still gapes in the chest and pulls around my breasts. How does one do an FBA for this dress? Add more width and widen the area that's gathered, so there's more room in the bust but it still comes in at the ribs?

Hmmm... Must get a good book on fitting before sewing up Simplicity 3562. I've read a lot of blogs that recommend Fit for Real People. That may have to be my next purchase.