I once saw a mounting system I really liked which allowed for more panels in the existing space, panels were mounted elevated above roof along each side with a unistrut system of mounting rails,
Underneath these panels was another layer of panels on cabinet Sliders like used for cargo and storage,
The lower panels could be pulled out to expose them to the sun, doubling the amount of active solar panels, spring loaded latching Pins, keep the lower panels in place retracted while travelling,
Panels could be released and extended using an awning pull rod, (before extending the awnings)
And pushed back to lock in place while travelling
Wish I had pictures to post, I have No Idea of the expenses, I only know the design basics and that it seemed to work extremely well