According to DWGS 25 and 30 I fit and drilled the F-739 and F-740 Forward Seat Floors to the seat ribs. These floors are removable to gain access to the control system, so they attach to the ribs with screws. The left floor (F-740) goes on first, with the wider right floor (F-739) on top.
Time: 2 hours.
Leonard's RV-7A Build 