Everthing was set up, so just riveted the aft spar components. Cleaned up from that; Placed upper aft skin in place to square-up wing skeleton.
Cut L-angles for both the upper and lower skins. Marked centerlines. Braced rear spar of wing high enough to get my hand underneath. Held L-angles in place, pilot drilled to #40. Once cleco'd in place, up-drilled to #30, the final size for this application.
Flipped wing over to check spacing of L-angles against the ribs to ensure nothing would hang up when removing/placing the skin. Deburred all L-angles and upper skin angle holes. Once riveted will set this skin aside for now.
Usually the bottom skin is done first, but I'll save some steps by doing the upper first, as far as the L-angles are concerned. Once the lower skin is riveted, all I have to do is put the upper skin in place and rivet, rather than having to first fit the L-angles.
Next up: rivet the L-angles and remove the skin in prep for lower skin tasks.