I dearly love Susan Partlan. http://www.stylemadebyhand.com/2013/02/16/correction-my-rotated-sleeve-cap-does-not-need-ease/ has the next piece to the sleeve puzzle. Namely, getting the sleeve to fit the biceps comfortably without messing up all the other fitting.
I’m also interested in her mathematical sleeve cap creation. I’m going to try a similar thing, but with 5 points.
1. The curve at the top of the armscye.
2. The point where the front of the armscye starts curving back under the arm.
3. The point where the back of the armscye starts curving forward under the arm.
4-5. The place where front and back meet to become the side seam.
(Side note, I’m starting from a bodice that fits as a sleeveless bodice.)