First task was to align the gusset to the lower edge of the F-713 auxiliary longeron. I couldn't quite slide it up far enough, though, because the notch in the side was interfering with the lower firewall weldment.

After notching it out another 1/8 inch so I could slide it into place, I got it all clamped up and ready to drill.

Hrm...this hole has some bad edge distance. I'll keep going and decide what to do about it later.

After drilling the hole pattern in the F-684 gusset, I peeled back the skin and match drilled through the F-601B-L-1 vertical firewall stiffener.

Dangit! This one hole ended up too close to the edge. This kind of burns me up. I modified this gusset exactly to the plans and now it has caused me to hose up a perfectly good part. Gonna have to call Van's about this tomorrow.