Illustration taken from
Internet Modeller October 99 issue. Well worth a look
Jasta 18 aircraft have been featured options in the 1/28 Revell and 1/48 Dragon/DML DVII kits. Three examples adorn the cover of the Windsock Datafile on the type. Though most agree that the basic finish, as so often on these occasions opinions differ on the detail. The wings are variously described as :
a) Upper and lower wings red on both surfaces
B) Upper and lower wings red on upper surface, lozenge beneath
c) Upper wing only red on upper surface, remaining wing surfaces lozenge.
d) All wing surfaces printed lozenge fabric.
Myself I lean towards option c), but it's your aeroplane and a real aeroplane not a model, whatever colour you paint it will be correct for that machine from now until forever.
Peter L