I think that as a minimum a snake should have an enclosure that is half the length of their body, but obviously bigger is better (with the exception of hatchlings who find security in small spaces). I think that you should upgrade to a 60cm enclosure rather than staying in the same set up or buying a bigger click clack. Too much messing around. One thing I would suggest if you have not done it already is provide some climbing perches for her. A lot of people believe that because Antaresia are terrestrial species they do not need perching, but I have found that my stimsons and spotted (and my woma and black headeds, also terrestrial) all utilise perching, although not as much as my carpets, jungles and diamond. This means they can utilise the height of the enclosure as well as the length so they can stretch out and get exercise making them happier and healthier. Finally, I would NOT put her with your spotted. Not only is it unwise to mix species, I would even be cautious of housing two childrens together full time, even if they are a pair because Antaresia are know to be cannibalistic. Apart from the fact that generally you will have greater breeding success if you only introduce animals for mating and house them separately the rest of the time. Hope this helps!