The stall warning switch assembly is made from a microswitch actuated by a stainless-steel lever, and supported by two brackets. I started by final drilling the holes in the brackets, and then countersinking 3 of the holes to accept flush-mounted screws. Next, I scuffed the brackets and primed them with paint. After drying, all of the screws, washers, and nuts were assembled according to the instructions.
Once I had the stall warning switch assembly together, I tried checking the fit in the left outboard leading edge wing section, but then I realized that something was not quite right. It looks like I've swapped just one of the left and right ribs for the two wing sections when building them, causing the rib webbing to be in the wrong place for the stall sensor to be mounted...
What's next? I think the best solution will be to just drill out these two ribs. swap them, and then rivet them back in the correct sides. That first means drilling out these 50 or so flush rivets perfectly without damaging anything.