I got out an old favourite jacket that's a very similar style to the one I'm making (pics from Me Made March '11):
Interestingly they were identical in the sleeve circumference at underarm level and the armhole size. The RTW jacket was longer up to the sleeve cap by about 2cm, and the shape of the upper sleeve on the RTW jacket was broader and longer. The RTW jacket was larger in terms of shoulder width and upper back width too (by about 3cm).
I made some changes to my pattern pieces and I was going to cut out a new set of muslin sleeves when I decided I couldn't bear to keep working with that disgusting shiny polyester muslin crap. So I'm afraid I've probably skipped some crucial fitting steps but I've moved onto the real thing - proper wool fabric! Here's a picture from just before cutting into the wool:
|and there's enough for mistakes too!|
And here are some progress shots - the sewing has commenced:
In these photos the peplum is only pinned in place - I need to attach the front facings before the peplum as the peplum front extends into facings that are just folded in place (if that makes sense). I've also sewed the front and back facings together, and the 2-piece sleeves + sleeve facings together, and have sewn up and pressed the bodice and sleeve linings... it feels like it's coming together now!
This final photo shows the sleeves pinned on (only just) and the facings sitting on top of the bodice - but I think it gives you an idea of how the jacket may look in a few more steps:
Happy Easter and happy sewing everyone!