I measured a client of mine for the Eve Classic (which I wrote about here) and she measures for a torso shape that is very skinny in the underbust and has a 6 inch difference between underbust and high/over bust (chest above the bust). Therefore, she needs a band with a "V6" torso shape modification. For more on torso shapes, read this post.  She has little to no body fat, so bras can easily be uncomfortable based on pressure against her ribs and sternum. 

I cut this band out to be able to customize based on every possibility. 

Note the extra inch of seam allowance added to the center front and the side seam for customization. The center front is designed to be cut on the fold, so the seam would go where you see the edge of the paper (1 inch seam allowance). The side seam has 1/4 inch seam allowances so adding an inch will give a seam allowance of 1 1/4 inches. In my next post about preparing to sew, I have actually marked all the stitch lines and written on the seam allowance amounts. 

I have done the back band a little differently than I have seen them done in the past. 

First, the side seam has an extra inch so now the seam allowance is 1 1/4 inches. Second, I have split the back band to add the ability to fit for a band alteration called by some as the "downward hike." I wrote about the downward hike in this post, but essentially it's just like the back dart in garments. Some people have athletic shoulder blades or a very curved small of the back or a dowager's hump and in those cases, a downward hike can give shaping to the back if that is also needed. I suspect this client may need this kind of shaping, but I wouldn't always cut this way for every client. 

Part 2