It strikes me that the Greek Fire used by Byzantine Fire Galleys may be quite different from the more generic form used by Arabs and others, as well as the Greeks. The specialized apparatus used to disperse the liquid leads me to believe that the ship-borne type was more evolved. Greek Fire has become a generic term for a form of Naptha like weapon used by many nations other than the Byzantines. Perhaps, for game purposes, we should limit its use to naval combats, as it seems the Byzantines did have an advantage with their specific form of Greek Fire in this respect. Anyhow, I can't find any source that I would take as definitive. Your sources are certainly as valid as mine. Perhaps, then, should Head Serf decide to include Greek Fire, it should be set up to best serve playablity instead of historical accuracy, as the historical record is incomplete in any case.