As rigid panels are not warrantied for this application, we recommend the Verditek flexible panel, as it is light - which will provide greater fuel economy, easy to install and provides reduced wind resistance. Although a flexible panel is more expensive, than a rigid panel, you are saving on the need for a mounting kit and is easy to install, with just a tube of Sikaflex.
We do not sell roof mounting kits, as we recommend the Verditek flexible panel, which is easy to install and does not require mounting.
This will depend on your roof space but also your requirements. Your energy needs will differ based on how often you use your vehicle. For occasional, light use, you will only require one panel but if you use you vehicle more regularly, you will have greater energy needs and will require more panels.