I’ve done one as well no problem, what I did was put some VHB tape on the rear (I work alone so chose this method to improve alignment) I marked the centre point of the panel top and bottom as well as the centre point on the fascia top and bottom. Offered the panel up to the fascia tacking on the top alignment mark and the panel to the top alignment mark on the fascia, then the same at the bottom, this made sure it was straight and not having to hold the 10ft panel up from one end (if that’s even possible 😉 ) then I pressed down the edges from centre to right end and then centre to left end, I added a screw to each corner to make sure it wasn’t coming off.
It will bend more than you think, they fold composite 90 degrees to make trays and it doesn’t crack so as far as the thickness will allow you to force it then it should be fine.[/list]