And Soviet Rifle Companies in defence deployed entrenched over 1 - 1.5 km often with a thickening of ATRs. About half that frontage in attack.
I am continually astonished at the low troop densities on the Eastern Front, even in a highly concentrated operation like Kursk.
A good reference for all this sort of stuff is
http://www-cgsc.army.mil/carl/resources/csi/glantz2/glantz2.asp