You said..."How long (if at all) before she starts to lay eggs?"...some females dig a few test holes first. Some dig one hole for more than a day before they lay the eggs. Often the female will start to lay them in the evening. Do not let her see you watching her when she is digging....it can make the female abandon the hole and this can push her towards eggbinding if it happens too often. Let her dig the hole, turn around with her nose out and lay her eggs. Then let her bury them and return to the branches. Then you can dig up the eggs.

One more thing...I always leave a container of washed playsand in the female's cage to show me when she is ready to lay. If the female can't lay the eggs when she is ready she can become eggbound.

Good luck!