never heard back from the original poster what the issue with the screws was. If its because they are not flush and the panel won't lay flat, I think you could just get some plexiglass or something that is the same thickness that the screws extend above the roof surface. Since you only put adhesive on an area about an inch wide around the panel and a little in the middle, you could glue a 2 inch strip of plexiglass around the perimeter where the panel will go, and few strips in the middle, to create a surface slightly higher than the screws, and then glue the panel to those. This might raise the panel1/4" above the roof but I would see no issue with that. It is certainly still much lighter and more aerodynamic than having heavy panels with an inch gap under them where wind buffets around and puts tremendous stress on the rack/mounting system.