After I got all of the skins drilled to the skeleton I wanted to install the tank bay skin stiffeners next but I didn’t have anyone at hand to support the skin while drilling through the stiffeners in the bay. Here’s what I did to do this job with no help:
Drill the stiffener to the main spar flange. Be sure you keep the stiffener straight while drilling. I blocked the aft end of the stiffener in the false spar with blocks and wedges to keep it tight against the skin.
Use straps to keep the skin pulled up tight toward the stiffeners.
Drill from the main spar down and cleco as you go to keep the skin and stiffener tight to each other.