Sandra Betzina Princess Seam FBA

I came across this article by Sandra Betzina: Today's Fit What Size are You? in which she demonstrates, among other things, this method for a princess seam full bust adjustment (aka fba):












I'm working on this princess shell from McCalls. McCalls M2818


I already did a standard fba but I still need a little more room in the bust so I'm going to try Sandra's.