Marked centerline on the F-705 bulkhead for platenuts. Used the jig to drill most. Single lug platenuts used in the corners and at junction with baggage ribs drilled with a platenut and screw as before. Used a dremel to make a small relief notch in the F-705 to allow me to set the rivets on the platenuts at the junction with the baggage ribs. Deburred all holes and dimpled for two-lug platenut rivets, countersunk for single lug. Touched up primer.