With my Sweetheart's help, I pinned the HBL horizontal and marked new lines for my neckline and armscye.
I have photographic evidence!
It looks kind of terrible in this picture but here's the result
I'm feeling pretty good about this. I can see I have to carve out a bit more of the back armholes but other than that I think I'm happy to leave it as it is.
It was so much easier fitting without any design elements and using the horizontal balance line. Yay!
Next up, drafting a sleeve!
Wish me luck.