Thanks to Jenna's fabulous article in the latest edition of Knitty, I now understand the theory behind sleeve-cap shaping. Jenna very patiently takes her readers through the process of calculating the height, width, and curve of a sleeve cap. Her article reassured me that the measurements I derived by using the calculations in Vogue Knitting are, indeed, realistic.
The cap shaping came down lots of sketching with a pencil and some graph paper.
Will it work? The proof will be in the knitting.