SEXING:
Probing with this species is almost always inconclusive and uncomfortable for the Corucia in question. Most likely the person will recieve an Extermely painful bite!!!
Head size if one has seen MANY skinks can be judged somewhat. The female tends to have a smaller, narrower head. This can be somewhat vaque by itself. The C/A ratio seems to a little better solidify this with the comparison to body girth (side Diameter of head over side diameter of body girth) Check previous posts for details. If I understand it correctly, over .77 indicates a male and under .77, a female. A male has generally a more streamlined body.
I believe Justin posted an idea using a known male shedded piece of skin and putting it in with the unknown skink(s). If Tail twitching and aggressive tendences commense, this indicates a male.
Circulus (There's that term again!) Establishment:
One male only can be set up with generally one to two females.
It is possible to do more females or establish (I don't know why)a large group of females. With the dimensions described, 3 at the max should be attempted to reduce stress. If 2 females to a male are set up, It could go either way. The male may breed with both females readily or may tend to breed only with the alpha female and keep the beta female in reserve.
Do more research in addition to this advice before you jump in.
Best of luck.
Tane