I added and notched all my extra 1/4" pieces before I assembled my wings. I used 3/16" thick 6061 for wing attach fittings, so my notches are slightly different from plans. I probably added more verticals than some other builders, but my ribs look pretty good epoxied to my spars. The diagonal in the 3rd photo is a brace for my fuel tank, so it is not shown in the plans. The U-shaped 1/8" thick ply doublers are 2" x 4-3/4"