If you need more than 2 times the number of qualified candidates because the current list of qualified candidates does not meet your selection criteria, you should:
Interview from your existing Participant pool.
You will only be charged for interviews you actually conduct.
Manually disqualify Participants.
Open up room for more qualified responses.
Copy your existing project.
Re-launch the new project with a more accurate screener.
Consider fine-tuning the nuances of your Target Audience.