The lowest price component in this Fuel Tank parts-list fiche is the Screw-pan-cros,3x8.
Some items from this specific schematic: Collar,6=16.1, Tube,5.3x10.5x850, Clamp, Bolt-flanged-small,6x.
With a quantity of six pieces, the Bolt,flanged,5mm is the most used part in the Fuel Tank diagram.