Most of my reference is for full dress but I'll kep digging till I find the feldgrau.
In German regiments, the NCO's rank insignia was a band of flat metalic lace in the button colour (white for the 1st). This was worn at the top edge of the "Swedish" cuff and at edge of the collar. In full dress the lace was at the top edge of the high collar, but the field grey uniform had a fold down collar, so it was at the bottom. Also a button with an heraldic badge was worn on the collar, in line with the shoulder strap button.The also carried a lance pennon with a state device.
In the pictureof the sergeant's uniforms, no4 is the Swedish cuff.
I thought I would include all of the state pennons. I know I shouldn't write on bucks, but sometimes you need to.
I realise your covering the pickelhaube but I included this because it's beautiful!!