If you check the textures use for the Tico in Model Viewer, the names are also constructed from a texture atlas, containing the abc letter, they are not fixed textures as far as I can tell, same with the number, the problem is the argument 66 drives an animation as far as I can tell, and this means the text and number is predefined (constructed) inside the edm file . So I can't do much :( Have not checked the Burke more closely yet.
Edit: and idea come to me while writing this, this is a hack, but what one could try, is to make a new livery , copy the names and numbers textures and just re-arange the letters and numbers :D what I mean for example we have CG-66 , so in the livery file use a texture atlas where 5 is where 6 is in the original atlas :D I won't go down that rabbit hole, but someone might.