I agree with Krusty. Make all the unit badges and nose art by hand--it looks much better. About the only exception would be perhaps for Marge on Bong's plane, which was a photo taped on in real life, and it's hard to get that look by hand.
I make 3-5 layers for this stuff--you can look at it and tell how many you need by how many things are stacked on top of each other. Say the unit shield for NJG1. I put the outline border on the top layer, the diving hawk on the next layer down, then the red lightning bolt's layer, then the globe section's layer, and finally the background black, for 5 layers. But I usually draw the main device 1st on whatever layer it needs to be on (such as the hawk here), then build the rest of the badge around it, including the border.