I live the van life full time out.
Fitting solar panels to roof rack.
Both cone connector sizes are available at big box hardware stores.
200w of solar panels on the roof rack installing the solar panels is done by using unistrut cone connectors 1 4 inch or 3 8 inch to attach to the slotted steel l brackets.
The solar panel mounts are bolted onto the rack so we can swap in new brackets if we want to upgrade our panels or remove them completely and have a cargo rack.
The second option is called a comp out where your installer will remove the tiles where you intend to put solar then lay down composite shingle to install the array.
In order to fit thicker 3 8 bolts into the 1 4 holes on the hightec solar panel we drilled out the hole with a 3 8 bit.