I don't know if it was discussed before but I used water colors on a Dr.I I did several years ago.
The colors a bit off but the effect is nice and with water color, you can add or take away the amount of color and streaking until it's just right. Just hit it with some clear lacquer and you're set. Similar to oils really but not as messy and much thinner.
-I also know the fuselage markings are wrong but it was before I had seen the side photo of this plane, the one in the Osprey book. All I had was the Windsock Dr.I Special to go on :P