Riveted doubler onto false spar. Layed out tank bay false spar extension for larger bay. Cut and fit, drilled, and attached. Attached inspection holes on underside. Attached false spar. Layed tank in bay, put cover on, found bay too wide front to back @ OB side. Removed false spar extension, layed in line with false spar using a straight edge instead of the rear spar. It moved the extension fwd about 5/16". Removed LE screws in front spar, put straps on to try and sqeeze it in tighter to ribs and move tank lid attachment strip rearward.