Not as bad as you might think compared to the 3/2 coats of today. In the 50's three button sack coats were cut fuller than the 3/2 coats we see today.
Example: Southwick made a sack model called the "Warwick" which was fuller in the chest & waist and had softer shoulders than the "Douglas" model they sale today.
The "Warwick" was discontinued sometime in the 70's, but in my opinion it was a true "sack cut". :icon_smile: