I dont know too much about females but belly looks rather large to me, I'd say get a laybin in there asap.
There will be plenty of info on 'how to' online.
As you say that the cham has been resting its belly across vines whilst basking the last few days whereas normally it lies on it, looking like it had one 2 many christmas dinners even though not eatten too much as it seems to have gone off food. 2 superworms and 2 medium locust only today not fussed about wanting anything else even though it was eatting like a horse 2 days ago 10 locust and 2 superworm and looking like it still wanted more as it sat waiting where it comes to be hand fed
Beautiful cham btw!