On my 2020 AF 865 I used the AM Solar L foot rocker foot mounts. I have 2 Zamp 170 watt panels at the rear and 1 70 watt panel in front of the refrigerator vent. The mounts make it easy to remove panels if needed. Their mounts have VHB tape on them. I used the tape along with #8 screws with Dicor all over the base of the mount after they were attached. Take a magnet and run it over the area where you want to place the panel mounts. Northwood places sheet metal in certain places for roof mounted items. I got a roof schematic from Northwood and it showed where all the sheet metal was. 9000 miles later the panels are still in place.
Jeff D