Hello,
I read your project requirements. I can tell you that I have over 8 year experience in Web development(PHP, MYSQL, HTML, CSS, JS/JQUERY/AJAX), and over 6 years in Wordpress. I currently manage over 30 Wordpress sites for my clients, so I can easily make changes in "WP Pro Quiz" plugin your require. I can do the required job in max 2 days. Feel free to ask me anything, I'll be more than happy to answer all your questions.