Allen is spot on, it can get complicated as other colours are sometimes seen, including Green and Red.
I have found this site rather useful. This link is for the page on SG 4, but there is a lot of other info on the site.
And you might want to check out the Fw 190 GB. Theres been 1 190 from SG 4 in the same scheme your doing, and there’s a lot of knowledge in there about 190’s.