Coat Sleeves - How Long?

[Lafont]

In regard to previous posts, someone at Burberry has actually volunteered to research the true size and approximate age of my vintage Burberry raincoat. I've sent her copies of the tags, etc.
Now, what is anyone's opinion as to how long should the sleeves be on a man's outerwear coat (probably all coats - dressy or otherwise, such as topcoat, trench coat, overcoat, raincoat, etc.)? Where in relation to the knuckle or wrist? And please clarify it you mean hands down, alongside the torso and standing, or sitting, etc. If one is wearing a sportcoat obviously the sleeves should be shorter than long-sleeved shirt sleeves, but should the coat sleeve be longer than the sportcoat or suit jacket sleeve, shorter, or the same?

 

[Bird's One View]

Overcoat sleeves should be longer than the sleeves of every garment worn under them. There is some allowance for individual preference, but I have seen the rule stated that they should extend about 2/3 the distance between the wrist bone and the kunckles. They look too long to me if they reach the webbing between the thumb and hand. (All measures taken standing with the arms relaxes at the sides.)