Hi Toby,
That's a nice little kit, I don't recall any major problems with it. The wing fit is a little fiddly but that's about it, and you'll need to add the small strengthening struts to the undercarriage that was typical of Jasta 2 aircraft.
I'm not sure about the recommended blue base for the upper surface streaking. I believe one or two Dr.Is were painted this way, and I have a pic of it (can't find where I got it from) which does show some very light streaks so it's possible. One thing for sure, the wing streaks ran directly fore and aft, not at an angle as shown in the instructions.
Have fun!
Ian