So I'm guessing her last shed was end of June? When palpating for eggs I've found them to feel like squishy water balloons nearer laying, and slugs are more noticeably hard.

Substrate wise I wouldn't worry too much - newspaper is fine, or they end up moving it all and laying on the floor of the tub anyway... Mulch is recommended for maternal incubation as it's good for holding humidity, less crucial if you're using an incubator.

This is my first season too, all I can say is be ready to wait! All my girls have been weeks late in laying, one still making me wait now. It can be difficult to identify the various stages and I am forever second guessing myself - hope your patience pays off!