Got new Lexan (.093) to reduce oil canning when flying. Considered using small machine screws with a nylon washer, then , after lots of discussion, opted to use pop rivets with a tinnerman washer. This requires countersinking the Lexan.
Finally got holes lined up and drillled to correct size on aluminum door frame (after changing mind from very small holes for machine screws). Next comes the actual countersinking and oversize holes so Lexan doesn't crack.