"Steve B" fired this volley in
:

It has to fit flat for attachment. If I had two little plate clamps,
maybe. But the larger ones hit the wall before the sheet does. This
needs to be hoisted in order to fasten it, and the hoisting device can
be no more than 1.25" or so thick.


Then don't drill through it and use hooks _through_ it, tack weld a couple
of hooks to the outside surface, and raise it up dead-flush to the work.
You can grind off the weldments afterwards.

LLoyd