I advise strongly against those flexible panels.
Get aluminum frame glass panels.
The flexible panels have a shorter warranty period for one. Flexing can break things inside, so flex it once and never again.
Putting those directly to the roof means a lot of heat builds up under them, enough to "burn" the roof (get it hot enough to discolor the roof), and heat will damage the panels (degrade them over time). Panels need air under them.
You can certainly use portable panels, but since you have all that roof space just install on the roof. Solar will keep your batteries always correctly charged/topped off so that is a huge plus also.
