I spent many years sorting out full bust adjustments. I still spend a long time on most patterns making full bust adjustments, but I'd branched out into other fitting challenges. When sewing up some Jenna cardigans this summer (not yet photographed or blogged, but I'm wearing the yellow one as I type), I kept narrowing the shoulder on every iteration. Finally, the blue version had a good shoulder fit, but it still fell off my shoulders if I didn't pull it on firmly.
That made me think some more about items which DO fit on my shoulders. I have a favourite Max brand green merino hoodie top. I measured the shoulders on that (they fit perfectly) and they were tiny shoulders. But because of the style of the hoodie, it didn't slip off easily. My Sewaholic Nicola dresses are slightly wide in the shoulders, but because of the little cap sleeve, they look fine.
Then I decided to have a go at a button through top. At first I was all set to go taping up the Muse Patterns Melissa dress. Then I decided that reviews that Melissa was on the wide shoulder side plus it was double princess seams to alter suggested it wasn't the perfect starter experience for princess seams. I bought the Blank Slate Novelista pattern and ran up a muslin.I altered the shoulder straight off as it seemed that shoulders were ALWAYS too wide on me.
First. Time. Shoulders were too narrow. So when I remeasured using the muslin on me, it turned out that I should have sewn up the blouse shoulders as printed. Fancy that! So now I am sewing the Novelista again, with a huge FBA to the princess seams, but shoulders as printed for the XL size. This time in fashion fabric.
I have a goiter which is quite prominent on one side of my neck and less so on the other side. Then I have shoulders which are quite differently shaped. So visual symmetry around my neck isn't going to happen. I think these aspects contribute to cardigans falling off me, and I will be conscious of this as I choose outer layer garment sewing patterns. Cardigans have been the most difficult item for me to find in a form that I actually like the fit and style, and maybe the neck issues are part of that.
I'm tempted next (as part of my desire to make another hoodie style merino top like my shop bought one) to make the Blank Slate Denver tunic, but altered to make a looser fit for the tunic. By the time I FBA those princess seams, I think I'd have a looser style front.