Cloth Luftwaffe Eagle, questions

I don’t actively collect TR items but do have a few in my collection.  
 

I have a few questions on EM/NCO cloth Luftwaffe eagles.  In reading various sites online, I find conflicting info.

- what is the difference in size between the cap and breast cloth eagle

- were they all on blue gray fabric (or black for Goring and ground crew)

- silver or white thread

- is there a difference between early, mid and late war for these eagles

Here are some photos of my particular eagle.  You can really see the blue-gray wool fabric when photo’d on a black background.

Also, the thread looks different on white background.

Thanks !