Spent more time on the wingtip ribs. Measured and drilled rivet holes for the left rib. New rivet spacer tool worth every bit of the cost; worked great. Fabbed a new flange for the portion removed that conflicted with the hinge. Planning to attach it to the outboard side of the rib to support the forward part of the rib. Struggled a bit with the location on the rib and hinge for the new flange. Began work on the placement of the right wingtip rib. Seems the sweet spot is right where the rib meets the fiberglass edge near the trailing edgeinside the wingtip.