I riveted the angle brackets to the outside skin. Installing the vertical angle brackets was quite a pain. My hand was simply too large to fit through the access holes. I ended up using tweezers to put the platenuts on the inside surface and clecoed in place.
Riveting was also a challenge. I couldn't get a bucking bar in place. I really wanted a bucking bar with some kind of handle on it. A bar with a handle! A hammer worked great - a hunk of iron on a stick.
I only installed a few screws as these all have to come out again to install the mid cabin floors.
