Prom I gave you sources about the average heights in general and that of the Roman army (check the links) . If you are trying to be historically accurate (I think that's your point isn't it?) you should just make Greeks and Romans the same (under the group Mediterrenean). Anthonius also pointed out that even among the Greeks who Adamantius an ancient physician calls moderate tall ,Macedonians and I ll quote Xenophon, Spartans were even taller than the mean Greek height.Joining the ranks of Greek armies also had height prerequisites as you might know.
It is also utterly unfair to base the mean Greek height on Pompey low class citizens whose origins it is impossible to know and furthermore they were not by any means indicative of ancient Greek soldiers.
I am trying to give you some historical credentials to your otherwise splendid job.It is your call.