http://www.ikatbag.com/2010/08/drafting-part-vi-fitting-sleeve-block.html has fantastic information on bicep ease and how it relates to the fitting of the armscye.
I highly recommend Lorraine’s pattern drafting tutorials. She’s the reason I finally figured out that a princess seam bodice would work best.
I’ve had a good-fitting princess-seamed dress for a long time now. It was originally my wedding dress and then I turned it inside out, put it back to front, removed the sleeves, reshaped the neck, dyed it (and $500 dollars later you will end up with a gown that is quite obviously a bridesmaid dress altered to be worn as a cocktail dress), and added front lacing. It’s a comfy medieval-esque dress that creates the right silhouette while being completely incorrect for the period it’s imitating.
But it made an excellent base for a princess-seam pattern. I traced the pieces using Glad Press ‘n Seal plastic wrap again. The front in the picture became the pattern for the back, back became the front. I did a sample muslin of one side to just below the bust. Then did an FBA and tried it again. Did another FBA and got a bodice that fits over my modern bra.The back fit perfectly the first time.
(Side-note: if I convert all the fullness to a single dart, it’s almost a right angle. The “basic bodice” about half-way down this page is hilariously different from what I get.)