I am looking for ways to attach components to the floor of a truck.
The floor could be as much as 1/4" thick plate with 1/2 inch or so
thick mat and sound deadening material. I want to be able to use
something like a drill screw or a threaded insert for two reasons. One
is that I want the person to be able to work alone and the other is
that many times it will be difficult to impossible for someone to get
access to the other side of the floor area. I would like the head of
the fastener have a positive grip such as a torx, hex head or square
drive.

Any ideas?