Finally back to the Regency pelisse.  The most important lesson learned was the shape of the set-in period sleeve.  I sewed up the bodice & one sleeve and discovered the sleeve pattern wanted to roll at the top giving an effect similar to the Elizabethan shoulder rolls.  I freehanded the original sleeve and because it was going to be full on top I didn't worry too much about the way period armseyes go deep into the back.  Combine this with the dropped shoulder and something odd happens.  I draped a new sleeve and took out all the cap fullness.  The new tailored sleeve squashes sideways at the top.  My underarm seam here is deliberately set to the back an inch to match the shifted side seam on the bodice. This gives a nice tailored sleeve but it fits small over the upper arm, which means wearing a big puffy sleeve garment underneath will be a problem, and it won't work on someone with big upper arms.  I haven't tried splitting longways and spreading because I like the trimmer look. 

This is the before and after in the actual fabric




Before, gathered sleeve cap

After, tailored set-in sleeve

I also draped the collar.  All of the extant collars I looked at were very high in back and usually displayed upright.  This is important because modern collars are bias to get them to lay softly.  We want to force the fabric to stand up so the center back grain needs to be upright and the side grain does as well, as much as possible. 

Start at the center back



Pin the fabric to the neckline to get the shape you want



What the foldover looks like

Trim & mark the muslin

I'm really happy with the lines in the back. The next challenge is to figure out how much I can cartridge pleat into the center back skirt panel.  I like really full coats but getting 60" into that center panel may be a challenge.