If she is eating, and locking, keep pairing her. If she starts refusing the males (you'll notice the lack of interest from them, too, as she will stop putting out pheromones to attract them), then you can stop pairing.

Be patient. Ovulations are easy to miss. Behavior is another key. Females building follicles tend to stay on the cool side and hug the water bowl. As the follicles develop, they may begin inverted basking (lying around on their back).

Once gravid, they tend to curl up on the heat, and may continue some inverted basking. Sometime before laying, they will make a 'nest'--they'll move all the bedding out of the way, and lay in a perfect spiral. Gravid females rarely eat.