I find it rather amazing and interesting that my skinks can all share a tank happily without clashing, territoriality, or stress. An adult male red-sided skink and True fire plus a juvenile true fire of unknown gender (possibly female) are all in the same tank, frequently hide together, and have not clashed.
The worst that has happened is Ozai (african red-sided skink), who in his hunger thought Iroh's (adult fire) tail was food, bit the ti which of course broke off in defensive autonomy. He spat it out when he realized it wasn't normal food and none of them have displayed any aggressive or territorial behavior.
Obviously I never intended for them to have to share the tank, it was a temporary situation when I was suddenly dropped 2 more. Pleasantly though, they all accepted each other entirely.
Will post pics soon.