Skin stiffeners and antenna doublers riveted to the Forward Bottom Skins. I had already enlarged the hole for the second comms antenna as I intend to fit a second box. In fact, having spoken to a Trig at the LAA Rally, I will fit a simple TY91 as my second box which can be controlled through the G3X Touch EFIS.
The Muffler Shroud Doublers are riveted to the Muffler Shroud Sides and then the Muffler Hanger Angles are riveted onto the sides and doublers. I back riveted the doublers and squeezed the 470AD4-5s to attach the hangers. These were difficult to squeeze straight and required careful alignment. I think they were a 1/2 size too long.