One thing the designer wanted to see was the neckline of the DB coat opened up and curved outwards to follow the waistcoat's neckline, and to keep the neckline of the waistcoat visible even when the coat is worn closed.
Usually a DB coat closes up the fronts a bit by virtue of the way the roll line travels from the gorge to the top button of the coat. To get the neckline to open up required what is essentially a dart running parallel to the roll line hidden under the lapel of the coat. The dart pulls the neckline into a curved shape rather than a straight line.
I also had a seamed on lapel which is very typical of the period so I needed to combine these requirements and all I can say is I am glad this isn't plaid.
Once I had the pattern to where I thought it should be, I cut a half muslin and tried it on the stand with the waistcoat it is worn with. I made a few additional changes and then I started into the velveteen, which I have to say is a wonderful weight to work with, and a low pile, so I have high hopes for the end result.
One thing I do when cutting heavily napped fabrics is to mark and cut the pieces singly. It does take a bit more time, but it is better than fighting with the two layers of fabric laying on one another.
Sometimes the top layer will look nice and flat but the under layer has either shifted or the naps are gripping each other. I think it also makes it easier for the tailor to mark- either with a line baste or with tailor tacks.