I'm not too sure about your colors... The upper surfaces seem almost black and white. I'd remove the balkenkreuz from the tail, it looks better blank than it does with the wrong thing there (in my opinion).
Also note that the tulip petals don't extend all the way to the end of the yellow. They extend about 2/3 the yellow.
The yellow card only appears on one side of the tail. The other side had an image of a bird over a nest of 3 chics (it's a flight school, right? The teacher and the students, get it?), and can be seen on the skin if you check out the JGr Ost skin in AH offline, or DL the one off of AH-Skins.com.
The yellow nose belongs more on the darker colors [EDIT: In my opinion], let me put a plate up, will edit this post in a few minutes.
EDIT: The colors would fall under either of 2 common schemes. One is more of a greyish scheme and I think it's more of a winter scheme, as we are talking about the Eastern Front. The other is more of a traditional camo pattern with green/grey. I'll just post a quick pic of each.
One interpretation of the lighter scheme One interpretation of the darker scheme