Today, with 9oz fabric, when you close the darts in the canvas, they must be first closed by hand with an Endel-stitch, so the edges will be drawn exactly together without gap. Then they will be covered with a thin lining bias stripe and zig-zaged with very thin overlook thread. This has to be done like a clock maker so fine. The closed darts have as good as nothing in thickness then and still you have to baste them under the chest dart to hide them. If you don't do that, you might see those darts in sight light as a very small bulge line, when you work with 9oz fabric.
If you make coats like Rory with 20oz carpet fabric, seen in his movies, it doesn’t matter how bad you close those darts. You can even overlap the edges, like in the old potato sack days, they will not be seen, when they basted under the chest dart.
Construction like, why should the canvas dart not be under the chest dart? I found it always a mystery to set the canvas dart 2cm aside from the chest dart. Those tailors said to bring the fullness on the side or more to the front because they didn't understand to place the chest dart at the right place and they didn't understand to cut the canvas supporting the fronts which is still very difficult to manage. I also felt into those mystery traps and had to believe first what the old masters had published, but I think they didn't even know what they did, continued repeating many mistakes of the old masters. You can make a mistake 100 years long, and still it will remain a mistake.
In order to understand the difference between crocked and straight, there is a thread in the forum, where it is exactly explained. Why should someone cut a modern coat crooked? Is it nice today to have all the fullness in the front and at the arm skye there is nothing. All the shape of the coat has to be brought in by shrinking the front edges and bridle then, at least the old masters cut a huge lapel dart to help it, plus they used 20oz carpet fabric, which were easily to be shrunk. The straight cut was invented to bring half of the fullness from the front edges back to the armhole, so there was shrinking at the armhole and some shrinking in the bridle. The shrinking in the bridle can be eliminated by using a small lapel dart, but then the canvas has to support the lapel dart as well and I haven't seen published a canvas cut that will support the lapel dart. Only the Schneiderhandwerk gave a hint, how to solve that problem accurate. To cut a canvas correct is absolutely a science and I would advise Werner Losberg to follow first.
I take offensive to your statement "If you make coats like Rory with 20oz carpet fabric, seen in his movies, it doesn’t matter how bad you close those darts".
It is not a 20oz carpet fabric, the cloth is from Aristan weight 320 gr/mtl 100% merino wool, cloth number A870/ 15, contact James Sheed, email@example.com for a sample.
I doubt you are a sewing tailor anyways just another novice sitting around reading books and think you are of the same league.
I don't make German coat, I make British, being Irish and training on Savile row thats what I have been exposed to. Am not saying their work and ideas doesn't have merit, its just not my way of making.
When you produce your video series on how you think a coat should be made, you can prove to the world why your system is better. Aside from that it would seem you are full of hot air.