Called Van's to get approval on alignment methods before drilling holes. Double checked all dimensions for squared and centered placement. Drilled 3/8" holes through forward floor panels, lower longerons and box weldments for outboard brackets and wear plates. Drilled 5/16" holes through forward floor panels and bolt weldments. Match-drilled 1/4" holes in weldments through inboard wear plates from underneath. Final-drilled 1/4"pilot holes through bottom skins and match-drilled forward floor panels, lower longerons and box weldments for outboard wear plates. Deburred all holes.