Having just returned from a visit with my husband's relatives, during which the sum total of my creative output was that I started the same sock three times, I'm all charged up to get something done in the sewing room. So it's back to the Vogue 8804 muslin, and the puzzle of those sleeves.
Here is the sleeve cap shape, when the two pieces are aligned.
And here it is compared with the cap of another Claire Shaeffer sleeve (V7908).
So I thought ... what if I rotated the sleeve front clockwise, until the cap shape is about the same as the other sleeve? And pinched out width from the cap down in the front sleeve only? So I tried it.
To my considerable surprise, pinching out the fullness from the front sleeve at the over-arm seam takes care of the weirdness at the hem. Don't ask me why, but it worked.
I transferred the change to the tissue, using purple pen (original seam lines in orange).
If you click on this, it enlarges somewhat and you may be able to see the purple dots that represent the location of the pins in my muslin. I connected them roughly with my french curve and found that to get a line that made any sense, I had to take a sliver of width out of the back too. The corrected curve flows nicely into the existing curve at the vent. I made an executive decision to the effect that even though my alteration takes slightly less width out of the upper sleeve than I pinned out, it will probably be OK.
So I cut it out.
And then I started thinking about the trim. This trim business is not The Sewing Lawyer's forté. It requires hours in fabric stores but not looking at fabric. So far I have chosen thread which I hope will blend into the base fabric and become invisible, and buttons which I really like but which may not be exactly right (depending on the trim). I also found some narrow ribbon trim embellished with sequins and beads (!!!!) which is surprisingly tasteful, but also rather expensive. I bought 10cm so I could think about it in more detail. It needs a base. So far the local stores have not produced a likely candidate.