One of the places I deviate from the Carden instructions is the socket supports on the truss sides. Carden has you attach them as you are building the truss. I install them as I am attaching the truss sides to the motor box. Let me explain...

After the first truss side is attached to the box at F5, F2 and F3, I side the sharpened wing tube phenolic through the motor box and use it to drill the hole through the balsa side. The processes is then repeated for the second side.

The socket supports are glued in using the phenolic as a guide. This ensures the supports, and holes in the fuse are at the correct angle.