Fit the Rib-Shaped Template B into leading edge of #4 (before outboardmost) LE rib. Marked the 2 locations on rib according to template. Drilled the 2 holes with #30 drill. Used rib as template to back-drilled on outboardmost (#5) rib for exact mirror-like alignment. Used clecos to attach nuplates in holes and final drilled #40 nutplates holes using nutplates as guide. Drilled the screw holes for the nutplates using a 3/16 drill bit. Deburred all holes. Cleaned with Mineral Spirits and Primed ribs Riveted the 4 mounting nutplates using AN426 solid rivets.