Bootstrap Responsive Layout and CSS project

We are looking for someone that pays meticulous attention to how the browser uses memory and optimize that part. We also need to make our website (based on bootstrap) fully responsive and cross-browser compatible. There is also a javascript piece. The big thing is that you will be in charge of keeping the site responsive. This is an ongoing project. Contact us to review. We would like to break up into modules for fixed payments and rapid development. We are also developers and understand planning and how to explain the tasks, so the scope should be clear.