The first version of this corset was finished last month, and mailed off. At the time I sent it I had concerns about whether or not it would fit, because the needed shaping was proportionally different from the conical stays I had made previously. Interestingly, this pair of stays, which were ordered shortly afterward, were made for a customer with similar proportions but on a larger scale. Following the methods described in my tutorial on drafting a conical corset block, I found that the angle created by the waist to the underbust was wider at the bust than the modified bust. This meant the angle needed to be brought in slightly, or the bust would be too loose. For the first version I made the design as normal (except ignoring the waist-to-underbust line on the front side of the stays) and waited to see how it actually fit to make any needed changes to the draft.
What I found was that a well defined natural figure from underbust to waist meant that in the raw measurements almost all the added bust circumference was actually in the bust rather than distributed around the torso. This placed the armpit further back than typical. It also meant that the underarm height needed to be raised due to the sharp angle of the side of the stays, which put the actual height lower than appeared in the pattern.
Thus, the altered pattern has an underarm height that is about 1″ higher than the bust height mark on the draft. I also reversed which side of the stays were defined by the modified bust measurement. The back side is angled to the modified bust measurement (the shorter distance), while the front side is angled by the bust-underbust line. The peak of the transition from bust to armpit is also nudged back a little further than typical, and the shaping was further smoothed at the request of the customer.