Well, for battle models, each character can have up to 10 textures(they have 2 by default).
Cloud for example will have 2 textures by default (if I'm not mistaken) which is rtac (Texture ID - 0) and rtad (Texture ID - 1).
So if your game is still fresh, you have 8 empty textures left to use for battle model, from rtae (Texture ID - 2) until rtal.. or something
.
As for that rtam.. I have no idea
. Wasn't that Cloud's hip/something?