Assistance with Selenium Webdriver and Python

I currently have a program written using the following stack: Ubuntu Python 3 Xfvb Selenium WebDriver 2.4.3 Mozilla Firefox 31 Modify Headers extension for Mozilla Firefox For the most part, this program has performed as expected, but I have been experiencing issues with headless Firefox hanging intermittently when being used in conjunction with Selenium. From my research, it appears that switching to the Chrome WebDriver will solve these issues. However, the program has the following requirements: - The browser must be able to connect to the Internet through different proxy servers on demand, preferably without modifying the Ubuntu network configuration. - Selenium WebDriver does not support modification of HTTP headers. Therefore, there must be another mechanism for modifying the HTTP headers before GET requests are made. I am not looking for coding help for this project, per se. I am looking for someone who has experience with the above stack and can point me in the direction of a practical solution. I'm not looking to change this stack unless absolutely necessary, so you must have experience with all of the above.