Your rudder crosses should extend forward onto the tailfin, and as stated, the red should extend much further back, all the way to the opening for the MGs.
I like your shade of blue, but your red should be much brighter. My guess is probably the same shade of red that Jasta 11 used for its markings- nice and bright, almost a vermilion.
I would also get rid of the information block on the tail, as that was usually painted over and they didn't care about repainting it. Rudder, ok, but fuselage, no.