So, I've done several alterations until I was sort of happy with it.
Then I did a rip and remark, another fitting, another alteration - and now I am (again) almost happy.
Especially under the arms is a lot of excess material left - which my arms push down and thus it makes diagonal folds at the sides of the back part.
Shall I cut it away, or is there another trick to not let that access material distort the fit of my coat?
( @Benjamin 's hint about waist suppression is normally absolutely valid, alass, in this case I can rule out waist suppression) * Photos is rather tricky, being home alone, might add those later on
You’ll need to increase the shoulder angle by the same amount. Front shoulder for the drop, take half of this amount at the neck point and crooken it the same amount.