I have just added the girl on the side of the muscat, unfortunatly i dont know how to create a livery so if you want to add this just replace the PNG file in the zip in this location.
Steam Version
C:\FlightSimulator\Official\Steam\flyingiron-spitfire\SimObjects\Airplanes\flyingiron_spitfire\TEXTURE
The file to replace is called EXTERIOR_1001_ALB.PNG
Make a backup of this file before swapping if you dont like.
This is just something i wanted to add and thought id share it.
Thanks