I made a few rivets out of copper
wire to attach the rivetnuts for
the rear access cover.
They weren't pretty but they worked.
The little spacers were used so that
the rivnuts would accept flat head
screws.
Since I made these I've
found you can get rivnuts from ACS
that take flat head screws, all you
have to do is dimple the skin.
I've used those on other covers.