Okay.....I made my daughter a sundress this spring. She's a 44DD and notoriously hard to fit. The pattern she picked out, unknown to me until I started cutting out the pattern pieces, has a side zipper!!!!! I don't like zippers. I really don't like side zippers. However, it came out really nicely.
(McCall's 6085 - not as short as the short dress, but not as long as the long one either)
I don't have a photo of her wearing it, at least not that I can remember....but if I can find one, I'll come back and post it.
Anyhow, when I had it all made, and adjusted up for her boobage, I had her come try it on. Well, underneath the biggest part of her bust we had a problem - the dress in that part and at the top of the skirt was too big. What I ended up doing was taking out the zipper, tapering the top part of the dress inward from the top of it to where it attached up to the skirt, and then tapering it out again so it would fit the large of her abdomen. I'd never done it before but I knew I had to do something to make it look better.
Anyhow, what I used to do before, when I wasn't quite as confident that I could fix my screw-ups, was to make a muslin only not necessarily out of muslin....whatever was really cheap and available at the time....and then if I really butchered it badly, it wasn't such a letdown as if I'd used expensive fabric. Sometimes the only way to learn is to make mistakes. Learning the boob adjustments for her has been easier than for me. She has bigger shoulders and a bigger chest. I am a full size and part of another size smaller on top than on the bottom.....except in my arms. This really complicates things since I have to alter up the sleeves if I make the top smaller but if I make it the same size as the bottom and the sleeves my B-cups disappear in the mountains of fabric. I'm slowly but surely learning how to adjust the fit for this problem. I just recently learned to increase a sleeve so it's looser on the bottom without looking ghastly on top. Heck, by the time I'm 80, I should have this all figured out!!