I make no claims to be particularly knowledgeable about this subject, but I thought I'd pass along two images from Charles Schaedel's
Men and Machines of the Australian Fying Corps 1914-19 that may be of interest.
The photo is of Camel C127, and gives a good view of size and shape of the emu emblem. The drawing is of Pup B1764, and shows the kangaroo emblem on a
black backgound. I don't know what source was used for the profile.