I make rounded back adjustments to my patterns and have no sewing partners so this can be difficult. It usually took several tries before I got it approximtly correct. I gave up one one pattern and measured from my neckbone to my waist and then measured my pattern from the seamline to the waist mark and spread the cut on the pattern to match. This method has worked well on my last several projects. It has certainly saved me a lot of time and effort.