This is an interesting jacket with the multiple back jacket pieces. It feels like piecing a quilt. All back pieces have been stitched together. One piece, the side back panel piece, did create a small issue and is due to the pattern not quite matching up the way it should.
While pin fitting the pattern pieces previously, I found this pattern piece not working well with the back panel piece it is attached to. I thought that part of the issue is where I transition from medium to large and in part it is. However when I matched up the original pattern piece, not my traced version, to the other original panel piece using same size I found that there is a fitting issue as result of the pattern draft. Even with the adjustment I made to my traced pattern piece there was still an attachment issue but very solvable.
I basted the side front piece to the back jacket unit at the shoulder and side seams. I just wanted to get a general idea of the fit. The instructions call for topstitching the back panel pieces and I plan to do this as I think it will help with the bulk/weight of this fabric. With several pattern pieces throughout the back area it will help this with the shaping also. I am using a faux suede fabric and the wrong side looks like twill or denim, so there is some weight to this fabric.
The pattern calls for it to be lined and I have not cut out the lining fabric yet. Sometimes when I am making a garment I sew up the lining first and fit that. This jacket lining has a solid back piece so I decided I needed to sew the back panel pieces first for better fitting.
I will baste the collar and front piece so I can be sure that if there are fitting adjustments needed to the back, I can make those before doing all the topstitching. That is a pain to remove those stitches to make those adjustments.
Updates later.