We recommend using two M6 Button Head Cap Screws to install the Side Mount onto aluminum mullion.
Amazon is a good source for the M6 rivet nuts (our bracket also work with ¼-20 rivet nut). Here is a link to order them:
The tool is also available on Amazon:
The M6 SHCS can be purchased form McMaster here:
McMaster usually have those in stock and ship the same day if you order before 5:30pm