Making a Chanel Jacket

I know there are some of you who have made Chanel jackets. I am a fan of Go Chanel or Go Home. The workmanship in the pictures posted is inspirational. Recently, I bought a fabulous Linton tweed and the woman who cut it for me asked if I was planning to make a Chanel jacket. Truth be told, I never really have been a fan of boxy styles on my body. But the more I read about Chanel jackets, and the the more images I see of celebrities wearing Chanel jackets on the internet, the more I am coming to realize that these jackets really are not so boxy. From what I understand, this is because the Chanel "pattern" makes use of a three piece sleeve and side panels which nip the jacket in against the body along the sides and against the arms at the underarm. I have decided to join the ranks of sewists who have attempted a Chanel inspired jacket. For my jacket, I would like to do a cropped style. Here is my fitted mock-up without sleeves and shoulder pads. I pinned out the extra shoulder height. I have since edited the pattern to include two inch side panels instead of side seams. Next, I attempted to alter the two piece sleeve pattern to have three pieces - one of which is two inches wide and runs down the underarm side of the sleeve. This is where I got stuck. I was up late last night trying to wrap my brain around a way to draft my own three piece sleeve from the two piece draft I have from Bernina My Label. I like the Chanel sleeve with the seam on the outside of the arm and the sleeve vent and buttons on the side as opposed to the back. I went to sleep thinking about how to redraft my sleeve pieces and this morning I woke up thinking I should just use a pattern. What do you think? Is it worth the bother? Can anybody tell me if they notice a difference between a two piece and a three piece sleeve? Can anybody recommend a good three piece sleeve pattern that is slim? I have thin arms and most jacket sleeves are roomy on me. Does anyone know of a sew along currently taking place for Chanel jackets? Can I join Go Chanel or Go Home? Or is it too late since I am just getting started? I am looking forward to working with that fabulous tweed, but the seeds of uncertainty are sprouting...