Breeches

[W.S.]

Looking at German WWI and WWII breeches, they look similar. The WWII breeches might be slightly wider. Am I wrong? If not, is there anything else that differs that actually matters? Or could one wear WWII breeches with a WWI tunic just like that? There might be the question of color, though. WWII breeches came in stone grey and field grey, and WWI breeches came only in stone grey. Or?